S494 Semiconductor Pulse Width Modulation Description The S494 is a monolithic integrated circuit which includes all the necessary building blocks for the design of pulse width modulate(PWM) switching power supplies, including push-pull, bridge and series configuration. The device can operate at switching frequencies between 1KHz and 300KHz and output voltage up to 40V. The S494 is specified over an operating temperature range of -40℃to85℃. Features • Uncommitted output transistors capable of 200mA source or sink • Internal protection from double pulsing of out-puts with narrow pulse widths or with supply voltages bellows specified limits • Easily synchronized to other circuits • Dead time control comparator • Output control selects single-ended or push-pull operation Ordering Information Type NO. S494 Marking S494 Outline Dimensions Package Code SOP-16 unit : mm PIN Connections 1. Non-INV Input 2. INV Input 3. Feed-Back 4. Dead-Time Control 5. CT 6. RT 7. GND 8. C1 9. E1 10. E2 11. C2 12. Vcc 13 Output Control 14. Ref Out 15. INV-Input 16. Non-INV Input KSI-K003-001 1 S494 Absolute Maximum Ratings Ta=25°C Characteristic Symbol Ratings Unit VCC 42 V supply voltage Voltage From Any Pin to Ground (except pin 8 and pin 11) Output Collector Voltage VIN VCC+0.3 V VC1, VC2 42 V Peak Collector Current IC1, IC2 250 mA Power Dissipation PD 1500 mW Operating Temperature Topr -40 ~ 85 °C Storage Temperature Tstg -65 ~ 150 °C Recommended Operating Condition Characteristic Symbol Min. Max. Unit VCC 7 40 V supply voltage Voltage on Any Pin Except Pin 8 and 11(Referenced to Ground) Output Voltage VIN -0.3 VCC+0.3 V VC1, VC2 -0.3 40 V Output Collector Current IC1, IC2 - 200 mA Timing Capacitor Ct 470 - PF Timing Capacitor Ct - 10 ㎌ Timing Resistor Rt 1.8 500 ㏀ fOSC 1 300 KHz Oscillator Frequency Electrical Characteristics Reference Section Characteristic Symbol Test Condition Reference Voltage Vref Iref = 1.0mA Line Regulation VLINE Load Regulation VLOAD Temperature Coefficient - Min. Typ. Max. Unit 4.75 5.00 5.25 V 7V < Vcc < 40V - 2 25 mV 1mA< IREF <10mA - 1 15 mV 0°C < Ta <70°C - 0.01 0.03 %/°C Min. Typ. Max. Unit Oscillator Section Characteristic Oscillator Frequency Oscillator Frequency Change Over Operating Temperature Range Symbol Test Condition fOSC Ct=0.01 ㎌, Rt=12 ㏀ - 10 - ㎑ Δ fSOC Ct=0.01 ㎌, Rt=12 ㏀ - - 2 % KSI-K003-001 2 S494 Dead Time Control Section Characteristic Input Bias Current (Pin4) Max. Duty cycle, Each Output Zero Duty Input Threshold Voltage Max Duty Symbol IIB(DT) DC(Max) VTH Test Condition Vcc = 15V, 0V < V4 < 5.25V Vcc = 15V, Pin4 = 0V, Output Control Pin = Vref - Min. Typ. Max. Unit - -2 -10 ㎂ 43 - 45 % - 3 3.3 0 - - V Error Amplifier Section Characteristic Symbol Test Condition Min. Typ. Max. Unit Input Offset Voltage VIOS V3 = 2.5V - 2 10 mV Input Offset Current IIOS V3 = 2.5V - 25 250 nA Input Bias Current IIB V3 = 2.5V - 0.2 1 ㎂ -0.3 - VCC V 60 74 - dB - 650 - ㎑ Input Common Mode voltage Range Large Signal Open Loop Voltage Range Unity Gain Band width VICR 7V ≤ VCC ≤ 40V GVO 0.5V ≤ V3 ≤ 3.5V fC - PWM Comparator Section (Pin3) Characteristic Inhibit Threshold Voltage Symbol VTHI + Test Condition Min. Typ. Max. Unit Zero duty cycle - 4 4.5 V Output Source Current Io 0.5V < V3 < 3.5V 2 - - mA Output Sink Current Io- 0.5V< V3 < 3.5V -0.2 -0.6 - mA Output Section Characteristic Output Saturation Voltage Common-Emitter Emitter-Follower Symbol VCE(SAT) Test Condition Min. Typ. Max. VE= 15V, IC = 200mA - 1.1 1.3 VC =15V, IE = 200mA - 1.5 2.5 Unit V Collector off-state Current IC(off) VCC = VC = 40V, VE = 0 - 2 100 Emitter off-state Current IE(off) VCC = VC = 40V, VE = 0 - - -100 VOCL - - - 0.4 V VOCH - 2.4 - - V ICC - - 6 10 mA ㎂ Output Control(Pin 13) Output Control Voltage Required for single-Ended or Parallel Output Operation Output Control Voltage Required for Push-pull operation Total Device Standby power Supply Current : These limits apply when the voltage measured at Pin 3 is with in the range specified. KSI-K003-001 3 S494 Output AC Characteristic Characteristic Symbol Common Emitter Rise Time tr Emitter Follower Common Emitter Fall Time tf Emitter Follower Test Condition Min. Typ. Max. - - - 100 200 - 100 200 - 25 100 - 40 100 Unit ns Block Diagram V cc 12 Ref Out 14 G ND 7 RT 6 13 R e fe r e n c e R e gu l a t or T F.F Os c CT 4 Non -i n v In pu t 1 In v -In pu t 2 Non -i n v In pu t 16 In v -In pu t 15 Fe e d-Ba c k 3 8 C1 9 E1 11 C 2 5 De a d T i me CO MP A R A T O R De a d-T i me Con t r ol O u t pu t Con t r ol 10 E2 + - EA 1 + - + PWM CO MP A R A T O R EA 2 + - KSI-K003-001 4 S494 INFORMATION The basic oscillator(switching)frequency is controlled by an external resistor (Rt) and capacitor(Ct). The relationship between the values of Rt Ct and frequency is shown in. The level of the sawtooth wave form is compared with an error voltage by the pulse width modulated comparator. The output of the PWM Comparator directs the pulse steering flip flop and the output control logic. The error voltage is generated by the error amplifier. The error amplifier boosts the voltage difference between the output and the 5V internal reference. See Figure7 for error amp sensing techniques. The second error amp is typically used to implement current limiting. The output control logic (Pin13) selects either push-pull or single-ended operation of the output transistors (see Figure6). The dead time control prevents on-state overlap of the output transistors as can be seen is Figure5. The dead time is approximately 3 to 5% of the total period if the dead time control(pin4) is grounded. This dead time can be increased by connecting the dead time control to a voltage up to 5 V. The frequency response of the error amps can be modified by using external resistors and capacitors. These components are typically connected between the compensation terminal (pin3) and the inverting input of the error amps(pin2 or pin15). The switching frequency of two or more S494 circuits can be synchronized. The timing capacitor, Ct is connected as shown in Figure8. Charging current is provided by the master circuit. Discharging is through all the circuits slaved to the master. Rt is required only for the master circuit. Operating Waveform KSI-K003-001 5 S494 Test Circuit Fig.1Error Amplifier Test Circuit + Fig.2 Current Limit sense Amplifier Test Circuit 1+ 1+ ERROR ERROR VIN V3 AMP 2 - + 16 + ERROR - V REF 2 - 16 + ERROR V IN AMP AMP 15 - 15 Fig. 3 Common-Emitter Configuration Test circuit and Waveform - Fig. 5 Dead-Time and Feedback Control Test Circuit 15V DC Vcc=15V 68 C Ea c h o u t p u t Trans is tor 150 12 2W 4 DEAD 8 Vcc TEST C1 TIME 9 Inputs 3 FEED BACK E1 12K 6 RT 5 CT 11 C2 10 1 (+) 0.01uF 2 E2 (-) 16 (+) 15 (-) 13 OUTPUT REF 14 CONTROL OUT 50K 7 GND Vc 15p F E 90% 90% 10% 10% Tr V3 AMP V REF - Tf 150 2W OUTPUT1 OUTPUT2 Fig. 4 Emitter-Follower Configuration Test circuit and waveform Voltage waveform 15V DC C Each output Trans is tor 90% GND VE 68 90% 10% 10% Tr 15pF KSI-K003-001 Tf 6 S494 APPLICATION CIRCUIT Fig. 6 Output Connections for Single-Ended and Push-Pull Configurations Q1 8 OUTPUT CONTROL 9 C1 TO OUTPUT VOLTAGE OF SYSTEM R1 1(16) + Vo QC E1 Q2 11 C2 0 < V OC < 4V Fig. 7 Error Amplifier Sensing Techniques 1 TO 500 mA(MAX) 10 E2 V REF 2(15) R2 QE ERROR AMP 3 POSITIVE OUTPUT VOLTAGE SINGLE-ENDED CONFIGURATION V REF Q1 8 2.4V<VOC<VREF 9 Q2 11 OUTPUT CONTROL C1 1(16) 250 mA(MAX) 3 E1 C2 NEGATIVE OUTPUT R1 VOLTAGE Vo Vo = -V REF R1 R2 E2 PUSH-PULL CONFIGURATION Fig. 8 Slaving Tow or More Control Circuits TO OUTPUT VOLTAGE OF SYSTEM Fig. 9Error Amplifier and Current Limit Sense Amplifier Output Circuits V cc 14 V REF 6 R2 2(15) 250 mA(MAX) 10 + V REF RT MASTER 5 RT 14 V REF CT 6 RT 5 CT TO REMAINDER OF ERROR AMPLIFIER CIRCUIT TO REMAINDER OF ERROR AMPLIFIER CIRCUIT CT SLAV E (ADDITIONAL CIRCUITS) 0.6mA KSI-K003-001 TO COMPENSATION PWM COMPARATOR INPUT 7 S494 Electrical Characteristic Curves Fig. 1 VCE(sat) -IC Fig. 3 tOSC - RT Fig. 2 VCE -IE Fig. 4 AVOL , Phase - f ∆ Ω φ Fig. 5 ICC - VCC KSI-K003-001 8 S494 These AUK products are intended for usage in general electronic equipments(Office and communication equipment, measuring equipment, domestic electrification, etc.). Please make sure that you consult with us before you use these AUK products in equipments which require high quality and/or reliability, and in equipments which could have major impact to the welfare of human life(atomic energy control, airplane, spaceship, traffic signal, combustion central, all types of safety device, etc.). AUK cannot accept liability to any damage which may occur in case these AUK products were used in the mentioned equipments without prior consultation with AUK. KSI-K003-001 9