Universal DC/DC Converter
AP34063
Note: 3.Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient temperature as
possible.
4.If the output switch is driven into hard saturation (non-Darlington configuration) at low switch currents ( ≤300mA) and high
driver currents ( ≥ 30mA), it may take up to 2.0 µs for it to come out of saturation.? This condition will shorten the off time at
frequencies ≥ 30kHz, and is magnified at high temperatures. This condition does not occur with a Darlington configuration,
since the output switch cannot saturate. If a non-Darlington configuration is used, the following output drive condition is
recommended:
Forced ß of output switch :
IC output
IC driver - 7.0mA*
≥ 10
*The 100Ω resistor in the emitter of the driver device requires about 7.0mA before the output switch conducts.
Representative Schematic Diagram
Drive 8
Collector
Ipk 7
Sense
6
VCC
Comparator 5
Inverting
Input
1 Switch
Collector
SQ
Q2
R
Q1
100
2 Switch
Emitter
Ipk
Oscillator
CT
Comparator
+
_
1.25V
Reference
Regulator
3 Timing
Capacitor
4
Gnd
(Bottom View)
Anachip Corp.
www.anachip.com.tw
Rev.A5 Feb.10, 2004
3/10