UC2842/3/4/5-UC3842/3/4/5
Figure 11 :
Off-line Flyback Regulator.
Power Supply Specifications
1. Input Voltage :
95 VAC to 130 VAC
(50 Hz/60 Hz)
2. Line Isolation :
3750 V
3. Switching Frequency : 40 KHz
4. Efficiency @ Full Load : 70 %
Figure 12 :
Slope Compensation.
5. Output Voltage :
A. + 5 V,
±
5 % : 1 A to 4 A load
Ripple voltage : 50 mV P-P Max.
B. + 12 V,
±
3 % : 0.1 A to 0.3 A load
Ripple voltage : 100 mV P-P Max.
C. – 12 V,
±
3 % : 0.1 A to 0.3 A load
Ripple voltage : 100 mV P-P Max.
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 R
2
to su-
press the leading edge switch spikes.
8/11
STMICROELECTRONICS [ STMICROELECTRONICS ]
