Figure 8-1 Oscillator

Figure 8-2 Open-Loop Laboratory Text Fixture

High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors must be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3.

Figure 8-3 Slope Compression

A fraction of the oscillator ramp can be resistively summed with the current sense signal to provide slope compensation for converters requiring duty cycles over 50%. Note that capacitor, C, forms a filter with R2 to suppress the leading edge switch spikes.

Figure 8-4 Off-Line Flyback Regulator

1. Input Voltage: 95 VAC to 130 VAC (50Hz/60Hz)
2. Line Isolation: 3750V
3. Switching Frequency 40 kHz
4. Efficiency, Full Load: 70%
5. Output Voltage:
   1. +5V, ±5%; 1A to 4A Load
   2. +12V, ±3%; 0.1A to 0.3A Load Ripple voltage: 100 mV P-P Max
   3. –12V, ±3%; 0.1A to 0.3A Load Ripple voltage: 100 mV P-P Max