MC34023, MC33023 V V CC in 16 15 Reference Vref Regulator V V CC CC 4 UVLO Clock 9.2 V 5 4.2 V Vref 13 UVLO V Oscillator C RT 14 6 CT Output PWM R 12 Q Ramp 7 1.25 V Comparator Power Ground S PWM Latch Error Amp Output 3 Error Current + 2 Amp Limit 11 Noninverting Input Current Limit Reference 9.0 mA Inverting Input 1 9 8 Current Limit/Shutdown Soft-Start 0.5 V R C 1.4 V SS Q Soft-Start Latch Shutdown S 10 Ground Figure 19. Representative Block Diagram CT Clock Soft-Start Error Amp Output Ramp PWM Comparator Output Figure 20. Current Limit Operating Waveformshttp://onsemi.com8