FUJITSU ASSP For Power Management Applications BIPOLAR Switching Regulator Controller (Switchable between push-pull single-end functions) MB3759
Contents
1. OPERATING TIMING Voltage at Cr 1 1 I I l l 1 OUTPUT 1 I I 1 1 M ow OUTPUT 2 MB3759 OSCILLATION FREQUENCY 1 2 fosc CT fosc kHz OUTPUT LOGIC TABLE GND Single ended or parallel output VREF Push pull MB3759 TYPICAL CHARACTERISTICS Reference voltage Vner V Oscillator frequency fosc Hz Reference voltage vs power supply voltage Reference change 0 10 20 30 40 Power supply voltage Vcc V Oscillator vs Rr Cr 1M 500 k 200 k 100 k 50k 20k 10k 5k 2k 1k 2k 5k 10k 20k 100 k 200 k 500 k 0 AVner mV Reference voltage change Reference voltages temperature AVner mV Duty radio Tow T 96 0 25 50 75 100 Temperature Ta Duty ratio vs dead time control voltage 0 1 2 3 Dead time control voltage V Continued MB3759 Open loop voltage amplification Av dB Collector saturation voltage V Open loop voltage amplification vs frequency 100 go A 80 70 60 50 40 30 20 0 10 100 1k 10k 100k 1M Frequency f Hz Collector saturation voltage vs c2. FUJITSU LIMITED For further information please contact Japan FUJITSU LIMITED Corporate Global Business Support Division Electronic Devices PLANT 4 1 1 Kamikodanaka Nakahara ku Kawasaki shi Kanagawa 211 8588 Japan Tel 81 44 754 3763 Fax 81 44 754 3329 htip www lujitsu co jp North and South America FUJITSU MICROELECTRONICS INC 3545 North First Street San Jose CA 95134 1804 U S A Tel 1 408 922 9000 Fax 1 408 922 9179 Customer Response Center Mon Fri Z am 5 pm PST Tel 1 800 866 8608 Fax 1 408 922 9179 http www fujitsumicro com Europe FUJITSU MICROELECTRONICS EUROPE GmbH Am Siebenstein 6 10 D 63303 Dreieich Buchschlag Germany Tel 49 6103 690 0 Fax 49 6103 690 122 http www fujitsu fme com Asia Pacific FUJITSU MICROELECTRONICS ASIA PTE LTD 05 08 151 Lorong Chuan New Tech Park Singapore 556741 Tel 65 281 0770 Fax 65 281 0220 http www 1 50 Korea FUJITSU MICROELECTRONICS KOREA LTD 1702 KOSMO TOWER 1002 Daechi Dong Kangnam Gu Seoul 135 280 Korea Tel 82 2 3484 7100 Fax 82 2 3484 7111 F0006 FUJITSU LIMITED Printed in Japan All Rights Reserved The contents of this document are subject to change without notice Customers are advised to consult with FUJITSU sales representatives before ordering The information and circuit diagrams in this document are presented as examples
3. lo Po PIN Vo lo VIN VIN lo Ton T UNTO Ton T 100 n 100 The theoretical conversion efficiency is 100 In practice losses occur in the switching element and elsewhere and design decisions to minimize these losses include making the switching frequency as low as practical and setting an optimum ratio of input to output voltage 11 12 MB3759 SWITCHING ELEMENT 1 Selection of the Switching Transistor It can be said that the success or otherwise of a switching regulator is determined by the choice of switching transistor Typically the following parameters are considered in selecting a transistor Withstand voltage Current Power Speed For the withstand voltage current and power it is necessary to determine that the area of safe operation ASO of the intended transistor covers the intended range for these parameters The speed switching speed rise time tr storage time tstg and fall time tf is related to the efficiency and also influences the power The figures show the transistor load curve and Vce Ic waveforms for chopper and inverter type regulators The chopper regulator is a relatively easy circuit to deal with as the diode clamps the collector A peak can be seen immediately after turn on However this is due to the diode and is explained later In an inverter regulator the diodes on the secondary side act as a clamp Viewed fro
4. Pulse max Single pulse Ic max 20 lt 9 10 lt lt 2 sa m 5 ica 2 1 2 05 O 0 2 0 1 0 05 5 10 20 50 100 200 500 1000 Collector emitter voltage Vce V 2 Selecting the Diode Consideration must be given to the switching speed when selecting the diode For chopper regulators in particular the diode affects the efficiency and noise characteristics and has a big influence on the performance of the switching regulator If the reverse recovery time of the diode is slower than the turn on time of the transistor an in rush current of more than twice the load current occurs resulting in noise spikes and reduced efficiency As arule for diode selection use a diode with a reverse recovery time tr that is sufficiently faster than the transistor t 14 MB3759 APPLICATION IN PRACTICAL CIRCUITS 1 Error Amplifier Gain Adjustment Take care that the bias current does not become large when connecting an external circuit to the FB pin pin 3 for adjusting the amplifier gain As the FB pin is biased to the low level by a sink current the duty cycle of the output signal will be affected if the current from the external circuit is greater than the amplifier can sink The figure below shows a suitable circuit for adjusting the gain is very important that you avoid having a capacitive load connected to the output stage as this will affect the response time VREF 2 Syn
5. current Vo pins 2 5 V Input bias current Vo pin3 2 5 V Common mode input voltage 7V lt lt 40 V Open loop voltage amplification 0 5 V lt Vo lt 3 5 V Unity gain bandwidth 1 rejection ratio CMR Vcc 40V Output sink ISINK current sink 5V lt 5 15 mV Vo 0 7V pin 3 ISOURCE source 15 mV lt Vip lt 5V Vo 3 5 V Output section Collector leakage current Vc 40 V Vcc 40V Emitter leakage current Vcc Vc 40 V 0 Collector Emitter emitter grounded Vsat c 0 200 mA saturation Emitter voltage follower VSAT E Vc 15 V le 200 mA Output control input current lopc Vi PWM comparator section Input threshold voltage 0 Duty Input sink current pin 3 Vo pins 0 7 V Power supply current V pin4 2 V See Fig 2 Standby current V pin6 VREF open Switching characteristics Rise time Fall time Ri 68 Q Ri 68 Q Rise time Fall time Ri 68 Q Ri 68 MB3759 15 V Ta 25 MB3759 LAGULLIULALULLALALIUUUL L ULULSAAGGISBUUAUISSISLLLLaceLALLLe GLA Miu H M TEST CIRCUIT 15V T 150 0 2 W 150 Q 2 W OUTPUT 1 o OUTPUT 2
6. of semiconductor device applications and are not intended to be incorporated in devices for actual use Also FUJITSU is unable to assume responsibility for infringement of any patent rights or other rights of third parties arising from the use of this information or circuit diagrams The contents of this document may not be reproduced or copied without the permission of FUJITSU LIMITED FUJITSU semiconductor devices are intended for use in standard applications computers office automation and other office equipments industrial communications and measurement equipments personal or household devices CAUTION Customers considering the use of our products in special applications where failure or abnormal operation may directly affect human lives or cause physical injury or property damage or where extremely high levels of reliability are demanded such as aerospace systems atomic energy controls sea floor repeaters vehicle operating controls medical devices for life support etc are requested to consult with FUJITSU sales representatives before such use The company will not be responsible for damages arising from such use without prior approval Any semiconductor devices have inherently a certain rate of failure You must protect against injury damage or loss from such failures by incorporating safety design measures into your facility and equipment such as redundancy fire protection and prevention of over current
7. recommended operating condition ranges Operation outside these ranges may adversely affect reliability and could result in device failure No warranty is made with respect to uses operating conditions or combinations not represented on the data sheet Users considering application outside the listed conditions are advised to contact their FUJITSU representatives beforehand MB3759 ELECTRICAL CHARACTERISTICS 15 V Ta 25 Parameter Condition Output voltage Vre lo 1 7 V lt lt 40 V 25 1 lt lo lt 10 25 20 lt Ta lt 85 Input regulation AVRIN Load regulation AVRID Reference Temperature stability AVR AT section Short circuit output Isc current Reference lockout voltage Reference hysteresis voltage Rr 30 Cr 1000 pF Standard deviation 30 Oscillator frequency 1000 pF section Frequency change 7 V lt Vcc lt 40 V with voltage 25 Oscillator frequency Frequency change with 20 C lt Ta lt temperature AIUSAAT 85 Input bias current 0 lt Vi i lt 5 25 V Maximum duty cycle Each Dead time output control section 0 duty threshold cycle Vi 0 Continued Continued Error amplifier section Input offset voltage Condition Vo pins 2 5 V Input offset
8. 24 V 925A 2200 uF 21 MB3759 2 Inverter regulator ZZ 2200 uF 0000009000000 10 2 10 kQ 16 100 ka IN1 0 22 22 ORDERING INFORMATION Part number MB3759P Package 16 pin plastic DIP DIP 16P M04 Remarks MB3759 MB3759C 16 pin ceramic DIP DIP 16C C01 MB3759PF 16 pin plastic SOP FPT 16P MO6 23 MB3759 WUSSV V PACKAGE DIMENSIONS 16 pin plastic DIP DIP 16P MO4 19 55 2030 C770 INDEX 1 D INDEX 2 6 20 0 25 244 010 4 36 172 0 51 020 MIN_ E 0 25 0 05 1 010 002 3 00 118 MIN i 0 46 0 08 U U U U U 018003 03938 1523 7 62 300 1P MAX 089 2 060 3 TYP 1 27 050 2 54 100 TOT TYP 1994 FUJITSU LIMITED 0160985 20 3 Dimensions in mm inches Continued 24 MB3759 Continued 16 pin ceramic DIP DIP 16C C01 c 19 30 58 760 4556 0
9. 64 025 salt REF y i 522 7 90 38 311 2206 5 08 200 MAX 0 81 0 30 032 012 0 250209 010 002 3 40 0 36 134 014 xy LI L L E 1 52 58 0 81 032 060 292 TYP 7 62 300 0 15 Lo l 2 54 0 25_ 0 46 os TYP 100 010 018 0s 1 27 050 17 78 700 REF 1994 FUJITSU LIMITED 0160119 2 3 Dimensions in mm inches Continued 25 MB3759 Continued 16 pin plastic SOP FPT 16P M06 ___2 25 089 10 15 925 400 08 05 002 STAND OFF A J gt INDEX 5 30 0 30 7 80 0 40 6 80 2520 209 012 307 016 268721 Y 1 27 050 0 45 0 10 0 15 002 0 50 0 20 TYP a 0181 004 21 0 13 005 W 0203 008 Details of A part Details of B part 0 40 016 I 0 15 006 l l 7 d 0 20 008 25010004 k0 201 008 8 89 350 0 18 007 0 18 007 0 68 027 0 68 027 L L 2000 FUJITSU LIMITED F16015S 20 5 Dimensions in mm inches 26 MB3759 lt
10. FUJITSU SEMICONDUCTOR DS04 27200 6E ASSP For Power Management Applications BIPOLAR Switching Regulator Controller Switchable between push pull and single end functions MB3759 DESCRIPTION The MB3759 is a control IC for constant frequency pulse width modulated switching regulators The IC contains most of the functions required for switching regulator control circuits This reduces both the component count and assembly work FEATURES Drives 200 mA load Can be set to push pull or single end operation Prevents double pulses Adjustable dead time Error amplifier has wide common phase input range Built in a circuit to prevent misoperation due to low power supply voltage Built in an internal 5 V reference voltage with superior voltage reduction characteristics PACKAGES 16 pin plastic DIP 16 pin ceramic DIP 16 pin plastic SOP DIP 16P M04 DIP 16C C01 FPT 16P M06 MB3759 a PIN ASSIGNMENT TOP VIEW 1 16 IN2 N1 2 15 IN2 3 14 4 13 oc 5 12 Vcc 6 11 7 10 E2 Ci 8 9 DIP 16P M04 DIP 16C C01 FPT 16P M06 BLOCK DIAGRAM Output control Dead time control Feed back MB3759 ABSOLUTE MAXIMUM RATINGS Parameter Condition Power supply
11. Rs 1 2 Vo S lL1 R2 Vo R1 Vo Vio alts u 2 Rs 1 where 2 gt gt R1 Viois the input offset voltage to the op amp 10 mV Vio 10 mV and this causes the variation in IL Accordingly if for example the variation in IL is to be limited to 10 96 using equation 1 and only considering the variation in the offset voltage gives the following A R1 Rs R2 This indicates a setting of 100 mV or more is required e Polarity change point Ie lo VIO VEE Rs R2 gt gt R1 As this is the point where the diode becomes forward biased it can be calculated by substituting R4 R3 R4 Vner Vo for Vo in equation where is the forward voltage of the diode 1 R4 R3 R4 VREF VD 2 Rs Rs Final limit current The limit current for Vo 0 when R2 gt gt R1 is the point where the voltages on either side of Rs and on either side of R5 are biased R4R5 VREF R3R5 Vp R4R5 Rs IL3 Se 8384 8385 8485 YO 1 1 R4 Vio 2138 VREF 2 Ea 3 Rs T2 Rs R4 Rs RS R sq eh Ed R3 R4 is the resistance formed by R3 and R4 in parallel R3R4 R3 R4 When R3 R4 lt lt R5 equation 2 becomes 1 R4 VREF VD Rs R3 R4 Rs In addition to determining the limit current ls for Vo 0 R3 R5 and diode D also operate as a starter when the power is tu
12. chronized Oscillator Operation The oscillator can be halted by connecting the Cr pin to the GND pin If supplying the signal externally halt the internal oscillator and input to the Cr pin Using this method multiple ICs can be used together in synchronized operation For synchronized operation set one as the master and connect the other ICs as shown in the diagram Master Slave VREF 3 Soft Start A soft start function can be incorporated by using the dead time control element MB3759 R2 Setting the dead time VREF Cd DT Rd Incorporating soft start When the power is turned on Cd is not yet charged and the DT input is pulled to the Vrer pin causing the output transistor to turn off Next the input voltage to the DT pin drops in accordance with the Cd Rd constant causing the output pulse width to increase steadily providing stable control circuit operation If you wish to use both dead time and softstart combine these in an OR configuration 4 Output Current Limiting Fallback system using a detection resistor inserted on the output side 1 Typical example VREF Rs E Vo R1 Vio He D R5 AW RAZ R2 _ _____ 0 GND 15 MB3759 Initial limit current lu VREF The condition for Vo is As the diode is reverse biased R1
13. efficiency This section describes the basic principles of operation using a chopper regulator as an example As shown in the diagram diode D provides a current path for the current through inductance L when Q is Transistor Q performs switching and is operated at a frequency that provides a stable output As the switching element is saturated when Q is on and cutoff when Q is off the losses in the switching element are much less than for a series regulator in which the pass transistor is always in the active state While Q is conducting the input voltage Vin is supplied to the LC circuit and when Q is off the energy stored in L is supplied to the load via diode D The LC circuit smooths the input to supply the output voltage The output voltage Vo is given by the following equation Ton Ton Vin mm Ton Toff T Q Switching element D Flywheel diode As indicated by the equation variation in the input voltage is compensated for by controlling the duty cycle Ton T If Vin drops the control circuit operates to increase the duty cycle so as to keep the output voltage constant The current through L flows from the input to the output when Q is on and through D when Q is off Accordingly the average input current Im is the product of the output current and the duty cycle for Q Ton T The theoretical conversion efficiency if the switching loss in Q and loss in D are ignored is as follows
14. levels and other abnormal operating conditions If any products described in this document represent goods or technologies subject to certain restrictions on export under the Foreign Exchange and Foreign Trade Control Law of Japan the prior authorization by Japanese government should be required for export of those products from Japan
15. m the primary side however a leakage inductance is present This results in an inductive spike which must be taken account of as it is added to double the Vi voltage chopper regulator inverter regulator IN L V W iol 2 Di vo K C C 02 VCE Ton 2 VIN MB3759 The figure below shows an example of the ASO characteristics for a forward biased power transistor 2SC3058A suitable for switching Check that the ASO characteristics for the transistor you intend to use fully covers the load curve Next check whether the following conditions are satisfied If so the transistor can be expected to perform the switching operation safely The intended ON time does not exceed the ON time specified for the ASO characteristic The OFF time ASO characteristic satisfies the intended operation conditions Derating for the junction temperature has been taken into account For a switching transistor the junction temperature is closely related to the switching speed This is because the switching speed becomes slower as the temperature increases and this affects the switching losses Forward biased area of safe operation single pulse 2SC3058A 450 V 30 A 25 C Ic
16. ollector output current 0 50 100 150 200 Collector output current Ic mA Low level output voltage Vo V Emitter saturation voltage Vsar E V Output voltage vs output current feed back terminal gt 4 F 5 Ta 70 3 3 5 gt eo 2 1 lt S pam 1 0 0 5 1 0 1 5 loi 0 5 10 15 Output current lot lon Emitter saturation voltage vs emitter output current 0 50 100 150 200 Emitter output current mA Continued 10 MB3759 Continued Power dissipation Pp mW Output voltage vs reference voltage Output voltage Vour V Le lt 2 0 1 2 3 4 5 6 Reference voltage Vner V Power dissipation vs power supply voltage 1000 lo IR 25 2000 mA a 200 10 400 10 200 5 100 5 600 109 5 100 0 400 0 0 200 0 0 10 2 3 40 Power supply voltage Vcc V Power supply current lcca mA Power dissipation Pp mW Power supply current vs power supply voltage 10 Icc 7 5 5 2 5 0 0 10 20 30 40 Power supply voltage Vcc V Power dissipation vs ambient temperature plastic DIP 0 20 40 60 80 100 Temperature Ta C MB3759 BASIC OPERATION Switching regulators can achieve a high level of
17. rned on Starter circuit The figure below shows the case when the starter circuit formed by R3 R4 R5 and D is not present The output current lo after the operation of the current limiting circuit is R1 Vo Ri R2 Rs 5 lo When Vo 0 such as when the power is turned on the output current lo Vio Rs and if the offset voltage Vio is positive the output current is limited to being negative and therefore the output voltage does not rise Accordingly if using a fallback system with a detection resistor inserted in the output always include a starter circuit expect in the cases described later MB3759 GND 2 Example that does not use a diode VREF Vo e ko Ri RA Vo R14R2 R3 R4 R3Z R1 R4 R2 GND The output current lo after current limiting is 1 R1 R4 R4 _ _ Vio R2 gt gt Ri Rs Ri R2 R3 R4 YO Wace YOn R4 In this case a current flows into the reference voltage source via and R4 if Vo gt Vaer maintain the stability of the reference voltage design the circuit such that this does not exceed 200 LA 17 MB3759 a rss r 3 When an external stabilized negative power supply is present lo Vo O Vo The output current lo after current limiting is lo 1 1 5 Rs R14 R2 VEE Rs Re gt gt R1 If the ou
18. tput is momentarily shorted Vo goes briefly negative In this case set the voltage across R1 to 300 mV or less to ensure that a voltage of less than 0 3 V is not applied to the op amp input 18 MB3759 5 Example Power Supply Voltage Supply Circuit 1 Supplied via a Zener diode VIN R Vz G A Vz Vcc MB3759 MB3759 Vcc Vz Vcc VIN Vz 2 Supplied via three terminal regulator d Three terminal regulator Vcc MB3759 6 Example Protection Circuit for Output Transistor Due to its monolithic IC characteristics applying a negative voltage greater than the diode voltage 0 5 V to the substrate pin 7 of the MB3759 causes a parasitic effect in the IC which can result in misoperation Accordingly the following measures are required if driving a transformer or similar directly from the output transistor of the IC 1 Protect the output transistor from the parasitic effect by using a Schottky barrier diode seb 19 MB3759 ma ax wwsuuww Z I mS n aro1zs 2 Provide a bias at the anode side of the diode to clamp the low level side of the transistor 44 3 Drive the transformer via a buffer transistor Vcc 3 7 Typical Application 1 Chopper regulator MB3759 100 V 5 1 Q
19. voltage 41 Collector output voltage 41 Collector output current 250 Amplifier input voltage Voc 0 3 Plastic DIP lt 25 1000 Power dissipation Ceramic DIP lt 60 C 800 lt 25 620 Operating temperature 85 Storage temperature 125 When mounted on a 4 cm square double sided epoxy circuit board 1 5 mm thickness The ceramic circuit board is 3 cm x 4 cm 0 5 mm thickness WARNING Semiconductor devices can be permanently damaged by application of stress voltage current temperature etc in excess of absolute maximum ratings Do not exceed these ratings RECOMMENDED OPERATING CONDITIONS Parameter Power supply voltage Collector output voltage Collector output current Amplifier input voltage FB sink current IsiNK FB source current souncE Reference section output current IREF Timing resistor Timing capacitor Oscillator frequency Operating temperature Note Values are for standard derating conditions Give consideration to the ambient temperature and power con sumption if using a high supply voltage WARNING The recommended operating conditions are required in order to ensure the normal operation of the semiconductor device All of the device s electrical characteristics are warranted when the device is operated within these ranges Always use semiconductor devices within their
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FUJITSU ASSP For Power Management Applications BIPOLAR Switching Regulator Controller (Switchable be