STC494 SUNTAC | Alldatasheet

Document overview

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Technical content

Features

ΘUncommitted output transistors capable of 200mA source or sink! ΘInternal protection from double pulsing of out-puts with narrow pulse widths or with! supply voltages bellows specified limits! ΘEasily synchronized to other circuits! ΘDead time control comparator! ΘOutput control selects single-ended or push-pull operation!

Ordering Information

Type NO. Marking Package Code STC494 STC494 SOP-16 O u t l i n e D i m e n s i o n s u n i t : mm PIN Connections 1. Non-INV Input 2. INV Input 3. Feed-Back 4. Dead-Time Control 5. C T 6. RT 7. GND 8. C1 9. E1 10. E2 11. C2 12. Vcc

13 Output Control

  1. Ref Out 15. INV-Input 16. Non-INV Input

S A b s o l u t e M a x i m u m R a t i n g s Ta=25qC Characteristic Symbol Ratings Unit supply voltage V CC 42 V Voltage From Any Pin to Ground (except pin 8 and pin 11) VIN V CC+0.3 V Output Collector Voltage V C1, VC2 42 V Peak Collector Current I C1, IC2 250 mA Power Dissipation P D 1500 mW Operating Temperature T opr -40 ~ 85 qC Storage Temperature T stg -65 ~ 150 qC Recommended Operating Condition Characteristic Symbol Min. Max. Unit supply voltage V CC 7 40 V Voltage on Any Pin Except Pin 8 and 11(Referenced to Ground) VIN -0.3 V CC+0.3 V Output Voltage V C1, VC2 -0.3 40 V Output Collector Current I C1, IC2 - 200 mA Timing Capacitor C t 470 - PF Timing Capacitor C t - 10 ༲ Timing Resistor R t 1.8 500 ༮ Oscillator Frequency f OSC 1 300 KHz

Electrical Characteristics

Characteristic Symbol Test Condition Min. Typ. Max. Unit Reference Voltage Vref Iref = 1.0mA 4.75 5.00 5.25 V Line Regulation V LINE 7V < Vcc < 40V - 2 25 mV Load Regulation V LOAD 1mA< IREF <10mA - 1 15 mV Temperature Coefficient - 0qC < Ta <70qC - 0.01 0.03 %/qC Oscillator Section Characteristic Symbol Test Condition Min. Typ. Max. Unit Oscillator Frequency f OSC Ct=0.01 ༲, Rt=12 ༮ - 10 - ༩ Oscillator Frequency Change Over Operating Temperature Range ȟfSOC Ct=0.01 ༲, Rt=12 ༮ - - 2 % G STC494

Characteristic Symbol Test Condition Min. Typ. Max. Unit Input Bias Current (Pin4) I IB(DT) Vcc = 15V, 0V < V 4 < 5.25V - -2 -10 ༟ Max. Duty cycle, Each Output DC (Max) Vcc = 15V, Pin4 = 0V, Output Control Pin = Vref 43 - 45 % Zero Duty - 3 3.3 Input Threshold Voltage Max Duty VTH - 0 - - V Error Amplifier Section Characteristic Symbol Test Condition Min. Typ. Max. Unit Input Offset Voltage V IOS V 3 = 2.5V - 2 10 mV Input Offset Current I IOS V 3 = 2.5V - 25 250 nA Input Bias Current I IB V 3 = 2.5V - 0.2 1 ༟ Input Common Mode voltage Range VICR 7V d VCC d 40V -0.3 - V CC V Large Signal Open Loop Voltage Range GVO 0.5V d V3 d 3.5V 60 74 - dB Unity Gain Band width f C - - 650 - ༩ PWM Comparator Section (Pin3) Characteristic Symbol Test Condition Min. Typ. Max. Unit Inhibit Threshold Voltage V THI Zero duty cycle - 4 4.5 V Output Source Current Io + 0.5V < V 3 < 3.5V 2 - - mA Output Sink Current Io - 0.5V< V3 < 3.5V -0.2 -0.6 - mA Output Section Characteristic Symbol Test Condition Min. Typ. Max. Unit Common-Emitter V E= 15V, IC = 200mA - 1.1 1.3 Output Satur- ation Voltage Emitter-Follower VCE(SAT) VC =15V, IE = 200mA - 1.5 2.5 V Collector off-state Current I C(off) V CC = VC = 40V, VE = 0 - 2 100 Emitter off-state Current I E(off) V CC = VC = 40V, VE = 0 - - -100 Output Control(Pin 13) Output Control Voltage Required for single-Ended or Parallel Output Operation V OCL - - - 0.4 V Output Control Voltage Req- uired for Push-pull operation VOCH - 2.4 - - V Total Device Standby power Supply Current ICC - - 6 10 mA : These limits apply when the voltage measured at Pin 3 is with in the range specified. STC494

Characteristic Symbol Test Condition Min. Typ. Max. Unit Common Emitter - 100 200 Rise Time Emitter Follower tr - - 100 200 Common Emitter - 25 100 Fall Time Emitter Follower tf - - 40 100 ns Block Diagram ΃΃ΖΖΗΗΖΖΣΣΖΖΟΟΔΔΖΖ ΃΃ΖΖΘΘΦΦΝΝΒΒΥΥΠΠΣΣ ΀ΤΔ · ΔΔ ΃ΖΗ͑΀ΦΥ ͸Ϳ͵ ͵ΖΒΕ͞΅ΚΞΖ ʹΠΟΥΣΠΝ ͿΠΟ͞ΚΟΧ ͺΟΡΦΥ ͺΟΧ͞ͺΟΡΦΥ ͿΠΟ͞ΚΟΧ ͺΟΡΦΥ ͺΟΧ͞ͺΟΡΦΥ ͷΖΖΕ͞ͳΒΔΜ ͵ΖΒΕ͑΅ΚΞΖ ΁Έ; ͶͲ͢ ͶͲͣ ΀ΦΥΡΦΥ͑ʹΠΟΥΣΠΝ STC494

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 typica lly 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 STC494

Fig.1Error Amplifier Test Circuit Fig.2 Current Limit sense Amplifier Test Circuit Fig. 3 Common-Emitter Configuration Fig. 5 Dead-Time and Feedback Control Test circuit and Waveform Test Circuit G G G G G G G G G G G Fig. 4 Emitter-Follower Configuration Test circuit and waveform Voltage waveform G G G G G G G G G ͶΒΔΙ͑ΠΦΥΡΦΥ ΅ΣΒΟΤΚΤΥΠΣ ͦ͢Ρͷ ʹ Ͷ ͖ͪ͡ ͖͢͡ ͖ͪ͡ ͖͢͡ ΅Σ ΅Η · Δ ͖ͪ͡ ͖͢͡ ͖ͪ͡ ͖͢͡ ΅Σ ΅Η ͸Ϳ͵ ͶΒΔΙ͑ΠΦΥΡΦΥ ΅ΣΒΟΤΚΤΥΠΣ ͦ͢Ρͷ ʹ ͵ͶͲ͵ ΅ͺ;Ͷ ͷͶͶ͵͑ͳͲʹͼ ΃Ͷͷ ΀Ά΅ ΀Ά΅΁Ά΅ ʹ΀Ϳ΅΃΀ͽ ·ΔΔ ͙͚͜ ͙͚͞ ͙͚͜ ͙͚͞ ΅Ͷ΄΅ ͺΟΡΦΥΤ ͧͧ͢͢ ͦͦ͢͢ ͢͢͡͡ ͢͢͢͢ ͨ ͸Ϳ͵ ͦ͡ͼ ͣ͢ͼ ͟͢͡͡Φͷ ͦ͢͡ ͦ͢͡ Ͷ΃΃΀΃ Ͳ;΁ Ͷ΃΃΀΃ Ͳ;΁ ·ͺͿ ·΃Ͷͷ Ͷ΃΃΀΃ Ͳ;΁ Ͷ΃΃΀΃ Ͳ;΁ ·ͺͿ ·΃Ͷͷ STC494

G APPLICATION CIRCUIT Fig. 6 Output Connections for Single-Ended Fig. 7 Error Amplifier Sensing Techniques and Push-Pull Configurations G G G G G G G G G G G G G G G G G G Fig. 8 Slaving Tow or More Control Circuits Fig. 9Error Amplifier and Current Limit Sense Amplifier Output Circuits G G G ͥͥ͢͢ ·΃Ͷͷ ·΃Ͷͷ ;Ͳ΄΅Ͷ΃ ΄ͽͲ·Ͷ ·ΔΔ ·΃Ͷͷ Ͳ;΁ͽͺͷͺͶ΃ ʹͺ΃ʹΆͺ΅ Ͳ;΁ͽͺͷͺͶ΃ ʹͺ΃ʹΆͺ΅ ͺͿ΁Ά΅ ΀Ά΅΁Ά΅ ʹ΀Ϳ΅΃΀ͽ ΀Ά΅΁Ά΅ ʹ΀Ϳ΅΃΀ͽ Ͷ΃΃΀΃ Ͳ;΁ ·΃Ͷͷ ΄Ί΄΅Ͷ; ·΀ͽ΅Ͳ͸Ͷ ··΃Ͷͷ ΄Ί΄΅Ͷ; ·΀ͽ΅Ͳ͸Ͷ STC494

I G Electrical Characteristic Curves G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G G Fig. 5 ICC - VCC Fig. 3 t OSC - RT Fig. 2 V CE -IE Fig. 4 A VOL , Phase - f Fig. 1 V CE(sat) -IC STC494