Panasonic AN8049SH handbook
Contents
1. Allowable Vcc ripple 10M Allowable range when Vcc is 3 V T 1M gt o Ss 3 S 2 E o a 100k E x Allowable range when Vcc is 10 V 10k 0 1 2 3 4 5 6 7 8 Vec ripple voltage V AC V p p Panasonic Voltage Regulators AN8049SH E Usage Notes continued 3 Notes on MOS drive Since the AN8049SH channel 1 and 2 output circuits were designed to drive bipolar transistors the following points require care if this device is used to drive n channel MOS transistors directly 1 Use an n channel MOS transistor with a low input ca pacitance VIN Vout The AN8049SH is designed to drive bipolar transis Oo S tors and adopts a circuit structure that can provide a con stant current 50 mA maximum output source current gt gt Furthermore it has a sink current capacity of 80 mA maxi OUT1 2 mum This means that designs must be concerned about increased loss due to longer rise and fall times If a prob lem occurs an inverter may be inserted as shown in figure Figure 1 Output boosting circuit 1 to provide amplification 2 Use an n channel MOS transistor with a low gate thresh VN V OUT old voltage yo S E Since the AN8049SH OUT1 and OUT2 pin high level Vcc E output voltage is Vcc 1 0 V minimum low Vy MOS 1 4 f transistors with an adequately low on resistance must be TEE used Also if a l2. IM 100 90 80 f 190 kHz 70 amp Rr 3kQ 60 f 1MHz e 100k 7 au x A i Ry 7 5kQ 40 30 20 Ry 33 KQ lo 10k 0 10p In On 02 03 04 05 06 07 08 C F Vpr V DT3 pin voltage Maximum on duty fosc Maximum output duty Ry 23 KQ 100 95 90 80 90 70 S Du 00 E A 5 a 85 Du Du a A A 40 2 E 30 A 80 20 10 0 75 02 10k 100k M Vpr V fosc Hz fosc Maximum output duty fosc Maximum output duty Ry 7 5 KO Ry 33 kO 95 95 Du 90 90 Du S amp Du E F a A a 85 Duz a 85 S _ 3 a A EN S Du Du D 80 80 75 75 10k 100k IM 10k 100k IM fosc Hz fosc Hz 14 Panasonic Voltage Regulators AN8049SH E Application Notes continued 2 Main characteristics continued Rg Isocour Rg Isiour 0 100 io 90 80 20 L Moss L8V 70 lt 20 Z o LV oc lt l4 V E 24V amp CC 40 c 50 3 3 RB a 8v a o 30 60 20 8V 70 lav 10 4 1 8 V 2 4 V E 5 LLL 100 k 10k 100k 100 k 10k 100k Ry Q Ry Q Panasonic 15 AN8049SH Voltage Regulators E Application Notes continued 3 Timing charts Vcc pin voltage waveform 1 67 V Output short
3. S C P pin voltage waveform CTL pin voltage e waveform pr OSC DT OUT 1 2 pin voltage waveform Totem pole circuit output OUT3 pin voltage waveform Open collector output 16 Panasonic Voltage Regulators E Application Notes continued 4 Function descriptions 1 Reference voltage block AN8049SH This circuit is composed of a band gap circuit and outputs a 1 26 V typical reference voltage that is temperature compensated to a precision of 1 This reference voltage is stabilized when the supply voltage is 1 8 V or higher This reference voltage is used by error amplifiers 1 and 2 2 Triangular wave generator This circuit generates a triangular wave like a sawtooth with a peak of 0 7 V and a trough of 0 2 V using a capacitor Cr for the time constant and resistor Ry connected to the OSC pin pin 17 The oscillator frequency can be set to an arbitrary value by selecting appropriate values for the external ca pacitor C and resistor R4 This IC can use an oscillator frequency in the range 20 kHz to 1 MHz The triangular wave signal is provided to the noninverting input of the PWM comparator in each channel internally to the IC Use the formulas be low for rough calculation of the oscillator fre quency 1 fosc 0 8 x V Crx C x Rp x In 2 vom OSCH Hz t2 Discharge d 4 Rapid charge T Figure 1 Triangular oscillator waveform Note however
4. 6 section Panasonic 7 AN8049SH Voltage Regulators B Terminal Equivalent Circuits continued Pin No Equivalent circuit Description 1 0 5 CTL3 I Controls the on off state of channel 3 A delay can be provided in the power supply Vec turn on start time by connecting a capacitor between this pin and ground High See the Application Notes 9 section 7 Channel 3 tna 1 26 V x Cer MF 1 1 uA s r 1 26 V output operation This pin can also be used to control the 777 on off state with an external signal In that case the allowable input voltage range is from 0 V to Vcc Note that during U V L O and timer latch operation this pin is connected to ground through a 20 kQ resistor 6 CTL2 I Controls the on off state of channel 2 A delay can be provided in the power supply turn on start time by connecting Vcc a capacitor between this pin and ground p See the Application Notes 9 section High gt Channel 2 tpLy2 1 26 V X Cero MF 1 1 UA s 1 26 V output operation This pin can also be used to control the 777 on off state with an external signal In that case the allowable input voltage range is from 0 V to Vcc Note that during U V L O and timer latch operation this pinis connected to ground through a 20 KQ resistor 7 CTL1 I Controls the on off state of channel 1 A delay can be provided in the power supply turn on start time by
5. The PWM and PWM 2 comparators reverse the logic of their inputs when adjusting the on period of their respective output The output transistors are turned on during periods when the OSC pin pin 17 triangular waveform is lower than both of the corresponding FB pin pins 20 22 or 24 and the corresponding DT pin pins 2 3 or 4 The maximum duty is set to 86 internally but can be set to a value in the range 0 to 100 by inserting a resistor between the DT pin and ground or the DT pin and Vggr pin See the 6 Setting the maximum duty section later in this document The IC s soft start function operates to gradually increase the width of the output pulse on period during startup if a capacitor is inserted between the DT pin and ground See the 7 Setting the soft start time section later in this document Output 1 and output 2 blocks These output circuits have a totem pole structure A constant current source output with good line regulation can be set up freely by connecting current setting resistors to the RB pins pins 10 and 11 See the 2 Main characteristics section earlier in this document for details on the Rp vs Iso our and Rp vs Isiour characteristics Output 3 block This output circuit has an open collector structure An output current of up to 50 mA can be provided and the output pin has a breakdown voltage of 14 2 V CTL block This block controls the on off state of each channel See the 9 Sequential
6. as possible to provide a clean switching waveform to the switching device 4 Use longer lines for the low impedance side of the output voltage detection resistors Panasonic 25 AN8049SH Voltage Regulators E Application Notes continued 11 Differences between this IC and the AN8049FHN The pin arrangements differ The AN8049FHN is a alternative package version of this IC AN8049SH E Tes e ES E EG B BS 4 gt 6 6 0 BE 8 E 895 8 amp 8 mE Q E B E 5 9 a 8 5 B EB ZS Ss AN8049FHN en e E ENEE Z 4 4 6 gt 6 FB2 IN 1 FB1 S C P DT3 26 Panasonic Voltage Regulators AN8049SH E Application Notes continued 12 Error amplifier frequency characteristics Error amplifiers 1 and 2 Test circuit 40 10 uF 30 Vin oI V 5i 4 mVI OUT a 7 10 2 3 V3 E 0 10 20 180 135 90 o 3 45 0 LHH 45 1 Ok 100k IM 10M 100M Frequency Hz 2 Error amplifier 3 Test circuit 1V 40 30 10 uF 20 Vin oI amp 4mV p pl 2 10 g d C
7. ground lines and isolate the IC ground from the power system ground In particular during light load operation when the on duty is low switching noise can enter the system at the lower limit of the sawtooth waveform causing the operating frequency to vary every period and resulting in unstable control Take measures described as 1 and 2 below and assure that switching noise does not appear on the sawtooth waveform 1 Use a ground line separate from the power system ground for the capacitor and resistor connected to the OSC pin 2 Lower the OSC pin impedance by either decreasing the value of the resistor Ry or increasing the value of the capacitor Cr See the figures below Vin The frequency changes at each period Vour Lower limit voltage GND of the sawtooth wave during stable operation N Noise is picked up and the IC switches from charge to discharge operation 2 Modify the jl values of the 1 Use separate lines capacitor and resistor 2 Position input filter capacitors as close as possible to the Vcc and ground pins If switching noise cannot be suppressed even with exceptionally large capacitors or if there are limitations on the size of capacitors that can be used install an CR filter in the input to reduce switching noise Problems may occur if switching noise enters the IC by any route 3 Keep the length of the line between the OUT pin and the switching device as short
8. npn transistor Isooum2 The OUT2 pin output source current This is set by the resistor connected to the RB2 pin When Rg is 1 KQ Iso our will be 34 mA maximum Du The output 2 on duty Voisara The OUT3 pin saturation voltage 0 5 V maximum when lours is 40 mA Tour3 The OUT3 pin current This will be Vcc V spos Voisar3V Ros Du The output 3 on duty Icc The Vcc pin current 2 Ifthe IC is shorted to ground shorted to Vcc or inserted incorrectly either the device itself or peripheral components will be destroyed 2 Allowable Vcc ripple Vcc ripple due to the switching transistor being turned on and off can cause this IC s U V L O circuit which is biased by Vcc to operate incorrectly and can cause the S C P capacitor charging operation to fail to start when the output is shorted The figure shows the allowable range for Vcc ripple Applications should reduce Vcc ripple either by inserting a ripple filter in the Vcc line or by inserting a capacitor between the IC GND and Vcc pins and locating that capacitor as close to the IC as possible Note that the allowable range shown here is the result of testing the IC independently and that the allowable range may differ depending on the actual system of the power supply circuit Also note that this allowable range is a design target and is not guaranteed by testing of all samples 12
9. started by on off control t 1 26 V loua X E SCP Vscp V lee s 1 15 x Cscp HF L Short circuit detection time tpg 1 26 At power supply startup the output appears to be in the shorted state and the IC starts to charge the S C P pin capacitor Therefore users must select an external capacitor that allows the DC DC converter output voltage to rise before the latch circuit in the DER later stage latches In particular care is required if the gt t s soft start function is used since that function makes the startup time longer Figure 5 S C P pin charging waveform o nternal reference voltage On off control Voc y FB1 2 Output shutoff S C P comp Q1 FB2 High level detection comparator 777 VREF FB3 T S C P 777 Figure 6 Short circuit protection circuit 20 Panasonic Voltage Regulators AN8049SH E Application Notes continued 6 Setting the maximum duty The maximum duty is set to 86 internally to the IC However this setting can be changed to be any value in the range 096 to 10096 by adding an external resistor 1 To use a duty lower than the current duty 80 to 92 Insert the resistor Rpr between the DT pin and ground Determine the DT pin voltage for the required duty from the provided DT pin voltage vs maximum on duty characteristics in the 2 Main characteristics section and determine the v
10. that the above formulas do not take the rapid charge time overshoot and undershoot into account See the experimentally determined graph of the oscillator frequency vs timing capacitance value pro vided in the main characteristics section 3 Error amplifier 1 This circuit is an npn transistor input error amplifier that detects and amplifies the DC DC converter output voltage and inputs that signal to a PWM comparator The 1 26 V internal reference voltage is applied to the noninverting input Arbi trary gain and phase compensation can be set up by inserting a resistor and capacitor in series be tween the FB1 pin pin 24 and the IN 1 pin pin 23 The output voltage Vouri can be set using the circuit shown in the figure FB1 63 Nour RI Error amplifierl R2 comparator input Figure 2 Connection method of error amplifier 1 Step up output Panasonic 17 AN8049SH Voltage Regulators E Application Notes continued 4 Function descriptions continued 4 Error amplifier 2 FB2 This circuit is an npn transistor input error 22 amplifier that detects and amplifies the DC DC converter output voltage and inputs that signal to Nour a PWM comparator The 1 26 V internal reference R1 voltage is applied to the noninverting input Arbi indien trary gain and phase compensation can be set up Cn by inserting a resistor and capacitor in series be IN 26v To the P
11. 0 10 20 0 45 90 2 amp 135 180 225 1 Ok 100k M 10M 100M Frequency Hz Panasonic 27 AN8049SH Voltage Regulators R Application Circuit Example 2 gt lt D Pr aria o c 2 m 5 D o EE m o lt 28 Panasonic
12. 2 High level output voltage 1 Non Io 2 10 mA Rp l KQ Vec 1 V Low level output voltage 1 Vou Ip 10 mA Rg 1 KQ 0 2 V Output source current 1 Isoouni Vo 0 7 V Rg 1 KQ 34 29 24 mA Output sink current 3 Isiouri Vo 20 7 V Rp 1 KO 40 mA Pull down resistor 1 Ro 17 27 37 kQ Output 2 block Output duty factor 2 Du Ry 7 5 KQ C 680 pF 80 86 92 High level output voltage 2 Vom Ion 10 mA Rg 1 KQ Vec 1 V Low level output voltage 2 Voi los 10 mA Rg lt l KQ XXE 0 2 V Output source current 2 Loop Vo 20 7 V Rg 1 kO 34 29 24 mA Output sink current 2 Isiour Vo 20 7 V Rp 1 KQ 40 mA Pull down resistor 2 Ro 17 27 37 kQ Output 3 block Output duty factor 3 Du R 7 5 KQ Cr 680 pF 80 86 92 Output saturation voltage Vo sar lo 40 mA Se 0 5 V Output leakage current lorg V13 14 V 1 uA Short circuit protection circuit block Input standby voltage V sTBY 0 1 V Input threshold voltage V rupc 0 8 0 9 1 0 V Input latch voltage Vin 0 1 V Charge current Luo Vscp 0 V 1 43 1 1 0 77 HA On off control block Input threshold voltage Vonta 0 6 0 9 1 2 V CTL block Input threshold voltage V rnc 1 07 1 26 1 45 V Charge current ler Ver 20V 1 43 1 1 0 77 HA Whole Device Average consumption current Iccoorr Rn 9 1 KQ duty 50 4 2 5 5 mA Standby mode current Iccisp 1 uA Panasonic 5 AN8049SH Vol
13. 75 V Error amplifier 1 block Input threshold voltage 1 Noen 1 241 1 26 1 279 V Input bias current 1 Ig 0 1 0 2 uA High level output voltage 1 Veni 1 0 1 2 1 4 V Low level output voltage 1 Veni m E 0 2 V Output source current 1 Iso FB 1 38 31 24 uA Output sink current 1 Isirpi 0 5 mA Error amplifier 2 block Input threshold voltage 2 Nous 1 241 1 26 1 279 V Input bias current 2 Ip 0 1 0 2 uA High level output voltage 2 Neu 1 0 1 2 1 4 V Low level output voltage 2 VEL2 0 2 V Output source current 2 Iso 38 31 24 uA Output sink current 2 Loupe 0 5 mA Error amplifier 3 block Input offset voltage Vio 6 6 mV Common mode input voltage range Vicg 01 Vcc V 1 4 Input bias current 3 Ip 0 6 03 uA High level output voltage 3 Ver 1 0 1 2 1 4 V Low level output voltage 3 Nos 0 2 V Output source current 3 Iso 38 31 24 uA Output sink current 3 ISIGFB 3 0 5 mA Oscillator block Oscillator frequency four R 7 5 KQ Cr 680 pF 170 190 210 kHz 4 Panasonic Voltage Regulators AN8049SH E Electrical Characteristics at Vcc 2 4 V Cage 0 1 uF T4 25 C continued Parameter Symbol Conditions Min Typ Max Unit Output 1 block Output duty factor 1 Du Rr 27 5 KQ Cr 680 pF 80 86 9
14. Voltage Reg A Panasonic AN8049SH 1 8 volt 3 channel step up step down and polarity inverting DC DC converter control IC Unit mm R Overview The AN8049SH is a three channel PWM DC DC zo converter control IC that features low voltage operation 119900 10090 This IC can form a power supply that provides two step up outputs and one step down or polarity inverted output 5 5 0 3 7 50 3 0 1 hi T E g 2 with a minimal number of external components The O AN8049SH features the ability to operate from a supply TIETETETETE 9 50 f voltage as low as 1 8 V and thus can be operated from 1 12 two dry batteries 0 65 0 10 m DHT m 1 0 50 LL 0 50 A 92 01 E E Featu res Seating Se E S Seating plane Wide operating supply voltage range 1 8 V to 14 V High precision reference voltage circuit Mer pin voltage 1 SSOP024 P 0300A Error amplifier 1 5 e Surface mounting package for miniaturized and thinner power supplies Package SSOP 24D 0 5 mm lead pitch 7 8 mm x 6 8 mm xt 1 9 mm e Supports control over a wide output frequency range 20 kHz to 1 MHz On off sequence control pins provided for each channel for easy sequence control setup e The negative supply error amplifier supports 0 volt input Common mode input voltage range 0 1 V to Vec 1 4 V This allows the number of exter
15. WM tween the FB2 pin pin 22 and the IN 2 pin pin R2 Jb f comparator input 21 The output voltage Voy can be set using the E circuit shown in the figure Voup 1 26 x R R Figure 3 Connection method of error amplifier 2 Step up output 5 Error amplifier 3 This circuit is an pnp transistor input error amplifier that detects and amplifies the DC DC converter output voltage and inputs that signal to a PWM comparator Arbitrary gain and phase compensation can be set up by inserting a resistor and capacitor in series between the FB3 pin pin 20 and the IN 3 pin pin 19 The output voltage Vour3 can be set using the circuit shown in the figure Step down output Inverting output FB3 FB3 e VREFVOUT3 o RI R Error i 18 amplifier3 IN 3 To the PWM To the PWM RR nusqa bia RS nS eae comparator input comparator input GE WP D Von Se 077000 S Vour3 R SS e X VREF Vour3 VREF X EI Figure 4 Connection method of error amplifier 3 6 Timer latch short circuit protection circuit 18 This circuit protects the external main switching elements flywheel diodes choke coils and other components against degradation or destruction if an excessive load or a short circuit of the power supply output continues for longer than a certain fixed period The timer latch short circuit protection circuit detects the output of the error amplifiers If the DC DC converter o
16. alue of the external resistor Rpr from formula A Note that there is a sample to sample variation of 19 to 33 due to temperature characteristics and sample to sample variations of the internal resistors R1 and R2 However the direction of the sample to sample varia tions is identical for R1 and R2 Determine the size of the sample to sample variations in the DT pin voltage Vpr from formula B and estimate the size of the sample to sample variation in the duty from the provided DT pin voltage vs maximum on duty characteristics in the 2 Main characteristics section V Ror PE A VREF E 4 xy R RI Ro S RAR DT LU SV app VERES B a VREF ein ai ne DT RI 45 KQ 44kQ R2 Rot R2 55 KQ 56 KQ 2 To use a duty higher than the current duty 80 to 92 Insert the resistor Rpr between the DT pin and the Vggr pin Use formulas C and D to determine the value of the external resistor Rpr and the size of the sample to sample variations in the same manner as in item 1 above R Vmg Vor suus C De ub d VREF C X Vpr RI R R R2 M opaan D DT RR Rpr REF VREF 1 26 V RI Rpr DT R2 777 Panasonic 21 AN8049SH Voltage Regulators E Application Notes continued 7 Setting the soft start time The soft start time is determined by the value of the capacitor connected between the DT pin and ground OSC pin waveform DT pin waveform Vpr Soft start time tp m vd Use
17. arge Vgs is required one solution is to use OUTI2 a a transformer as shown in figure 2 and apply a voltage that is twice the input voltage to the IC s Vcc pin Voc 2 x Viy VD Figure 2 Gate drive voltage boosting technique E Application Notes 1 SSOP024 P 0300A package power dissipation Pp T 700 658 Glass epoxy printed circuit board 600 75 x 75 x t1 6 mm Raja 152 C W x Pp 658 mW 25 C z S 500 a Independent IC a without a heat sink 40 Raja 273 C W S 366 Pp 366 mW 25 C Z E 300 2 263 x 200 s X 146 V 100 s Te ES KA 0 Y 0 25 50 75 85 100 125 Ambient temperature T C Panasonic 13 AN8049SH E Application Notes continued 2 Main characteristics Timing capacitance Oscillator frequency Voltage Regulators DTI and DT2 pin voltage Maximum on duty
18. connecting Vcc a capacitor between this pin and ground See the Application Notes 9 Hist section e 7 Channel 1 tory 126 V x Cen 1EY 1 1 A 8 T 1 26V_ output operation This pin can also be used to control the 777 on off state with an external signal In that case the allowable input voltage range is from 0 V to Vcc Note that during U V L O and timer latch operation this pin is connected to ground through a 20 kQ resistor 8 Panasonic Voltage Regulators B Terminal Equivalent Circuits continued Pin No 8 100 kQ Equivalent circuit Start and stop of internal circuits 77 Description Off Controls the on off state When the input is high normal operation Vopr gt 1 2 V When the input is low standby mode Vopr lt 0 6 V In standby mode the total current consumption is held to under 1 WA AN8049SH 1 0 VREF Outputs the internal reference voltage The reference voltage is 1 26 V allowance 1 when Vcc is 2 4 V and I ggr is 0 1 mA Insert a capacitor of at least 0 1 uF between Veer and ground for phase compensation 10 enen Wor 30 KU 777 RB2 Connection for a resistor that sets the channel 2 output current Use a resistor in the range 750 Q to 15 kQ 11 enen 30 kQ IsitouT i RB1 Co
19. nal components to be reduced by two resistors e Fixed duty factor 86 However the duty can be adjusted to anywhere from 0 to 100 with an external resistor Timer latch short circuit protection circuit charge current 1 1 4A typical Low input voltage malfunction prevention circuit U V L O operation start voltage 1 67 V typical e Standby function active high control input standby mode current 1 LA maximum Alternate package versions also available Part No AN8049FHN Package QFN 24 0 5 mm lead pitch 5 4 mm x 4 4 mm xt 0 8 mm B Applications e Electronic equipment that requires a power supply system Panasonic 1 AN8049SH Voltage Regulators E Block Diagram i d Wi m O gt E O z E a ES Z E O gt gt A ooth wave generator 0 7 V 0 3 V Error RBI amplifier 1 u 77 OUTI 1 26V Error 18 amplifier 2 d OUT3 Error amplifier 3 RB2 OUT2 GND FB2 B Pin Descriptions Description Description 1 S C P Connection for the capacitor 12 OUTI OUTI block push pull output that provides the short circuit protection circuit time 13 OUT2 OUT2 block push pull output EC 14 GND Ground 2 DT3 Chan
20. nel 3 soft start setting 15 OUT3 OUT3 block open collector output 3 DT2 Channel2 soft start setting 16 Voc Supply voltage 4 DTI Channel 1 soft start setting CES 17 OSC Oscillator circuit timing resistor and 5 CTL3 Channel 3 on off control capacitor connection 6 CTL2 Channel 2 on off control 18 IN 3 Error amplifier 3 noninverting input 7 CTLI Channel on off control 19 IN 3 Error amplifier 3 inverting input 8 Off On off control 20 FB3 Error amplifier 3 output 9 Vrer Reference voltage output 21 IN 2 Error amplifier 2 inverting input 10 RB2 Connection for the OUT2 22 FB2 Error amplifier 2 output block output source current setting resistor 23 IN 1 Error amplifier 1 inverting input 11 RBI Connection for the OUTI 24 FB1 Error amplifier 1 output block output source current setting resistor 2 Panasonic Voltage Regulators AN8049SH E Absolute Maximum Ratings Parameter Symbol Rating Unit Supply voltage Voc 14 2 V Off pin allowable application No 14 2 V voltage CTL pin allowable application Ver Vcc 0 2 V voltage Error amplifier input pin Vin 6 V allowable application voltage Supply current Icc mA OUTI and OUT2 pin output Iso our 50 mA source current OUT3 pin output current lo 50 mA Power dissipation Pp 146 mW Operating temperature Topr 30 to 85 C Storage temperature Tote 55 to 125 sE Note 1 Do not apply external currents or voltages to any pins not
21. nnection for a resistor that sets the channel 1 output current Use a resistor in the range 750 O to 15 kQ 12 See pin 11 OUTI Push pull output The absolute maximum rating for the output source current is 50 mA The output source current is set by the external resistor connected to the RB1 pin Panasonic AN8049SH B Terminal Equivalent Circuits continued Pin No 13 See pin 10 Equivalent circuit Voltage Regulators Description OUT 2 Push pull output The absolute maximum rating for the output source current is 50 mA The output source current is set by the external resistor connected to the RB2 pin 1 0 14 GND Ground 15 OUT3 Open collector output The absolute maximum rating for the output current is 50 mA 16 Vcc Power supply Provide the oprating supply voltage in the range 1 8 V to 14 V 17 OSC Connection for the capacitor and resistor that determine the oscillator frequency Use a capacitor in the range 100 pF to 1 000 pF and a resistor in the range 3 kO to 33 kO Use an oscillator frequency in the range 20 kHz to 1 MHz 18 19 IN 3 Noninverting input to the error amplifier 3 IN 3 Inverting input to the error amplifier 3 20 10 FB3 Output from the error amplifier 3 This circuit can provide a source current of 31 uA
22. operation section later in this document Panasonic 19 AN8049SH Voltage Regulators E Application Notes continued b Time constant setup for the timer latch short circuit protection circuit Figure 6 shows the structure of the timer latch short circuit protection circuit The short circuit protection comparator continuously compares a 0 9 V reference voltage with the FB1 FB2 and FB3 error amplifier outputs When the DC DC converter output load conditions are stable the short circuit protection comparator holds its average value since there are no fluctuations in the error amplifier outputs At this time the output transistor Q1 will be in the conducting state and the S C P pin will be held at 0 V If the output load conditions change rapidly and a high level signal 0 9 V or higher is input to the short circuit protection comparator from the error amplifier output the short circuit protection comparator will output a low level and the output transistor Q1 will shut off Then the capacitor Cscp connected to the S C P pin will start to charge When the external capacitor Cscp is charged to about 1 26 V by the constant current of about 1 1 mA the latch circuit will latch and the dead time will be set to 10046 with the output held fixed at the low level Once the latch circuit has latched the S C P pin capacitor will be discharged to about 0 V but the latch circuit will not reset unless either power is turned off or the power supply is re
23. or a sink current of 0 5 mA minimum Panasonic Voltage Regulators AN8049SH B Terminal Equivalent Circuits continued Pin No Equivalent circuit Description 1 0 21 IN 2 I Inverting input to the error amplifier 2 22 FB2 O Output from the error amplifier 2 This circuit can provide a source current of 31 uA or a sink current of 0 5 mA minimum 23 IN 1 I Inverting input to the error amplifier 1 24 FB1 O Output from the error amplifier 1 This circuit can provide a source current of 31 HA or a sink current of 0 5 mA minimum Panasonic 11 AN8049SH Voltage Regulators E Usage Notes 1 Allowable power dissipation 1 Since the power dissipation P in this IC increases proportionally with the supply voltage applications must be careful to operate so that the loss does not exceed the allowable power dissipation Pp for the package See the Pp T curve Reference formula P Vcc V geg X Isooury X Duit Vcc V Beg X Iso ouro X Du Vo sar X lours X Dus Vcc X Icc Pp VpEQ1 The voltage between the base and emitter of the channel 1 npn transistor Iso ouri The OUT pin output source current This is set by the resistor connected to the RB1 pin When Rg is 1 KQ Loop will be 34 mA maximum Du The output 1 on duty VBEQ2 The voltage between the base and emitter of the channel 2
24. specifically mentioned For circuit currents denotes current flowing into the IC and denotes current flowing out of the IC 2 Items other than the storage temperature operating temperature and power dissipation are all stipulated for an ambient temperature T 25 C 3 1 T 85 C See the Application Notes for details on the relationship between IC power dissipation and the ambient temperature 2 When Vcc lt 6 V the following condition must hold Vj Vin 2 Vcc 0 2 V R Recommended Operating Range Parameter Symbol Range Unit Off pin application voltage Vorr Oto 14 V OUTI and OUT2 pin output source current Loan 40 to 1 mA OUT3 pin output current lo 40 max Timing resistance Rr 3 to 33 kQ Timing capacitance Cr 100 to 10 000 pF Oscillator frequency four 20 to 1 000 kHz Short circuit protection time constant setting capacitance Cscp 1 000 min pF Output current setting resistance Rg 750 to 15 000 Q Panasonic 3 AN8049SH Voltage Regulators E Electrical Characteristics at Voc 2 4 V Cage 0 1 UF Ta 25 C Parameter Symbol Conditions Min Typ Max Unit Reference voltage block Reference voltage Veer larr 0 1 mA 1 247 1 26 1 273 V Line regulation with input fluctuation Line Vcc 1 8 V to 14 V 2 20 mV Load regulation Load Iker 2 0 1 mA to 1 mA 20 3 mV U V L O block Circuit operation start voltage Vuon 1 59 1 67 1
25. t voltage will fall 2 All ICs are shut down when an output shorted state occurs For example if the IC1 output voltage falls its output short circuit protection circuit will operate and the latch circuit will latch When this happens the IC1 output stops and at the same time the sawtooth oscillator stops and the OSC pin is held fixed at about 1 2 V As a result the IC2 OUT1 to OUT3 pins temporarily go to the full off state and the DC DC converter output voltage will drop Finally the IC2 output short circuit protection circuit will operate and the latch will go to the latched state This behavior will also occur if the IC2 output falls first Panasonic 23 AN8049SH E Application Notes continued 9 Sequential operation 24 Sequential operation under the control of external capacitors Voltage Regulators Delays can be provided in the startup times by inserting capacitors Cc between the CTL pins and ground Delay time tp y 1 26 V x Gen UF 1 1 AA s AN8049SH Cera Coen zn ub ub Cena CCL lt Cora lt Cera Figure 8 Sequential operation using external capacitors U V L O cleared Panasonic Voltage Regulators AN8049SH E Application Notes continued 10 Notes on power supply printed circuit board design Careful attention must be paid to the following points when designing the printed circuit board layout to achieve low noise and high efficiency 1 Use extremely wide lines for the
26. tage Regulators E Electrical Characteristics at T 25 C continued Design reference data Note The characteristics listed below are reference values related to the IC design and are not guaranteed Parameter Symbol Conditions Min Typ Max Unit Reference voltage block Vpger temperature characteristics Vereat T 30 C to 85 C 1 Error amplifier 1 block V ry temperature characteristics V rnar Ta 30 C to 85 C 1 5 Open loop gain 1 Ay 80 dB Error amplifier 2 block Vry temperature variation VTHaT2 1 5 Open loop gain 2 Av 80 m dB Error amplifier 3 block Open loop gain 3 Ava 80 dB Oscillator block Frequency supply voltage fov Vcc 1 8 V to 14 V 1 characteristics R 7 5 kQ C 680 pF Frequency temperature for T 30 C to 85 C 3 characteristics R 7 5 kQ C4 680 pF Short circuit protection circuit block Comparator threshold voltage ViHL 1 26 V On off control block Off pin current IoFF Vogp 5 V 38 uA 6 Panasonic Voltage Regulators AN8049SH B Terminal Equivalent Circuits Pin No Equivalent circuit Description 1 0 1 Veo S C P O Connection for the capacitor that sets e the timer latch short circuit protection rane 1 1 pA Latch circuit time constant Use a capacitor EH E with a value of 1 000 pF or higher 126vLR Ou
27. the following formula to set the soft start time tp V R DT x L Vrer Vpr Fo tp R gt x Cpr x In 1 VREF 1 26 V one RI 45kQ 44 kO R2 55 KQ 56kQ RI R2 22 Panasonic Voltage Regulators AN8049SH E Application Notes continued 8 Parallel synchronous operation of multiple ICs Multiple instances of this IC can be operated in parallel If the OSC pins pin 17 and OFF pins pin 8 are connected to each other as shown in figure 7 the ICs will operate at the same frequency It is also possible to operate a one channel control IC e g the AN8016SH or AN8016NSH and a two channel control IC e g the AN8017SA or AN8018SA in this parallel synchronous mode In this case short the OSC and Off pins together OSC pins connected together OSC AN80495H AN8049SH S C P gt Off pins L connected together Figure 7 Synchronous parallel operation Notes on parallel operation 1 The remote on off state of each individual IC cannot be controlled independently In this sort of circuit always connect all the Off pins together and control the on off states of the multiple ICs at the same time The reason for this is that if for example IC1 is solely turned on off the sawtooth wave will be stopped temporarily and the OSC pin held fixed at about 1 2 V As a result the IC2 OUT1 to OUT3 pins will be forced temporarily to the full off state and the DC DC converter outpu
28. tput The charge current Luc is 1 1 WA 7T shutoff typical 2 DT3 I Sets the channel 3 soft start time Set the time by connecting a capacitor DEN between this pin and ground 44 kO PWM3 See the Application Notes 7 section i Note that although the channel 3 maximum on duty is set internally to 46 KQ e 86 the maximum on duty can be adjusted by connecting resistors between this pin and ground and between this pin and the Nor pin See the Application Notes 6 section 3 DT2 I Sets the channel 2 soft start time Set the time by connecting a capacitor O between this pin and ground See the Application Notes 7 section 45 KQ PWM2 Note that although the channel 2 maximum on duty is set internally to 55 KQ 8696 the maximum on duty can be 6 777 adjusted by connecting resistors between this pin and ground and between this pin and the Vpgp pin See the Application Notes 6 section 4 DTI I Sets the channel 1 soft start time Set the time by connecting a capacitor De de between this pin and ground 45 kQ PWMI See the Application Notes 7 section Note that although the channel 1 d 55 kQ maximum on duty is set internally to 86 the maximum on duty can be adjusted by connecting resistors between this pin and ground and between this pin and the Vsrr pin See the Application Notes
29. utput voltage drops and an FB pin pins 20 22 or 24 voltage exceeds 0 9 V the S C P comparator outputs a low level and the timer circuit starts This starts charging the external protection circuit delay time capacitor If the error amplifier output does not return to the normal voltage range before that capacitor reaches 1 26 V the latch circuit latches the output drive transistors are turned off and the dead time is set to 100 See the 5 Time constant setup for the timer latch short circuit protection circuit section later in this document Panasonic Voltage Regulators AN8049SH E Application Notes continued 4 Function descriptions continued 7 10 11 Low input voltage malfunction prevention circuit U V L O This circuit protects the system against degradation or destruction due to incorrect control operation when the power supply voltage falls during power on or power off The low input voltage malfunction prevention circuit detects the internal reference voltage that changes with the supply voltage level While the supply voltage is rising this circuit cuts off the output drive transistor until the reference voltage reaches 1 67 V It also sets the dead time to 100 96 and at the same time holds the S C P pin pin 1 and the DT pins pins 2 3 and 4 at 0 V and the OSC pin pin 17 at about 1 2 V PWM comparators The PWM comparators control the on period of the output pulse according to their input voltage
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Panasonic AN8049SH handbook