SL494 PWM Control Circuit The SL494 incorporates on a single monolithic chip all the functions required in the construction of a pulse-width-modulation control circuit. Designed primarily for power supply control, the SL494 contains an on-chip 5-volt regulator, two error amplifiers, adjustable oscillator, dead-time control comparator, pulse-steering flip-flop, and output-control circuitry. The uncommitted output transistors provide either common-emitter or emitter-follower output capability. Push-pull or single-ended output operation may be selected through the outputcontrol function. The architecture of the IL494 prohibits the possibility of either output being pulsed twice during push-pull operation. • • • • • • Complete PWM Power Control Circuitry Uncommitted Outputs for 200 mA Sink or Source Output Control Selects Single-Ended or Push-Pull Operation Internal Circuitry Prohibits Double Pulse at Either Output Internal Regulator Provides a Stable 5 V Reference Supply Variable Dead-Time Provides Control Over Total Range FUNCTION TABLE Output Control Grounded At Vref Output Function Single-ended or Parallel Output Normal Push-Pull Operation LOGIC DIAGRAM SLS System Logic Semiconductor ORDERING INFORMATION SL494N Plastic SL494D SOIC TA = -20°C to 85° C for all packages PIN ASSIGNMENT SL494 MAXIMUM RATINGS Symbol Parameter Value Unit 41 V VCC +0.3 V VCC Supply Voltage VI Amplifier Input Voltage VO Collector Output Voltage 41 V Collector Output Current 250 mA -65 to +150 °C Tstg Storage Temperature RECOMMENDED OPERATING CONDITIONS Symbol Parameter Min Max Unit 7 40 V -0.3 VCC - 2 V VCC Supply Voltage VI Amplifier Input Voltage VO Collector Output Voltage 40 V Collector Output Current (Each Transistor) 200 mA Current Into Feed back Terminal 0.3 mA CT Timing Capacitor 0.47 10.000 nF RT Timing Resistor 1.8 500 KΩ 1 300 KHz -20 +85 °C Oscillator Frequency TA Operating Free-Air Temperature SLS System Logic Semiconductor SL494 ELECTRICAL CHARACTERISTICS (Temperature -20 ∼ 85°C, VCC = 15 V, f=10 kHz)) Symbol Parameter Test Conditions Min Max Unit 4.75 5.25 V Reference Section Vref Output Voltage IO=1 mA Vregin Output regulation VCC=7 V to 40 V, TA=25°C 25 mV Vregout Input regulation IO=1 to 10 mA, TA=25°C 15 mV ∆Vref Output Voltage change with temperature TA= -20°C to 85°C 1 % ISC Short-circuit output current (Note 1) Vref=0 50 mA 14 KHz Oscillator Section fOSC Frequency CT=0.01 µF, RT=12 kΩ δfOSC Standard deviation of frequency (Note 2) All values of VCC, CT, RT, TA Constant 15 % δfOSC(∆V) Frequency change with voltage VCC= 7 V to 40 V, TA=25°C 10 % δfOSC(∆T) Frequency change with temperature CT=0.01 µF, RT=12 kΩ TA= -20°C to 85°C 2 % -10 µA 6 Dead Time Control Section IIB(2T) Input bias current (pin 4) VI= 0 to 5.25 V DCmax Maximum duty cycle, each output VI(pin 4)=0 V VTHD Input threshold voltage Zero duty cycle (pin 4) Maximum duty cycle 45 % 3.3 V 0 Error Amp Section VIO Input offset voltage VO(pin 3)=2.5 V 10 mV IIO Input offset current VO(pin 3)=2.5 V 250 nA IIB Input bias current VO(pin 3)=2.5 V 1 µA Common-mode input VCC= 7 V to 40 V voltage range A vol fb CMRR Open-loop voltage amplification LOW -0.3 HIGH VCC - 2 ∆VO=3 V, VO=0.5 to 3.5 V Unity-gain bandwidth V 70 dB 100 kHz Common-mode rejection ratio VCC=40 V, TA=25°C 65 dB IO Output sink current (pin 3) VID=-15 mV to -5 V, VO(pin 3)=0.7 V 0.3 mA IO+ Output source current (pin 3) VID=15 mV to 5 V, VO(pin 3)=3.5 V -2 mA SLS System Logic Semiconductor SL494 ELECTRICAL CHARACTERISTICS (Temperature -20 ∼ 85°C, VCC = 15 V, f=10 kHz)) Symbol Parameter Test Conditions Min Max Unit 4.5 V PWM Comparator Section VTHP II Input threshold voltage (pin 3) Zero duty cycle Input sink current (pin 3) VO(pin 3)=0.7 V 0.3 mA Switching Characteristics trc Output voltage rise time Common-emitter configuration 200 ns tfc Output voltage fall time Common-emitter configuration 100 ns trf Output voltage rise time Emitter-follower configuration 200 ns tff Output voltage fall time Emitter-follower configuration 100 ns Output Section IC(off) Collector off-state current VCE=40 V, VCC=40 V 100 µA IE(off) Emitter off-state current VCC=VC=40 V, VE=0 -100 µA VSAT Collectoremitter Commonemitter VE=0, IC=200 mA 1.3 V saturation voltage Emitterfollower VC=15 V, IE=-200 mA 2.5 VI=Vref 3.5 mA mA IOCH Output control input current Total Device ICC Standby supply current ICCA Average supply current All other inputs & VCC=15 V 10 outputs open VCC=40 V 15 V(pin 4)=2 V 17 mA Notes: 1. Duration of the short circuit should not exceed one second. 2. Standard deviation is a measure of the statistical disribution about the mean as derived from the formula N ∑ (x - x) 2 n n=1 σ = N-1 SLS System Logic Semiconductor