Universal DC/DC Converter

AP34063

Anachip Corp.

www.anachip.com.tw

Rev.A5 Feb.10, 2004

3/10

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 :

≥ 10

*The 100Ω resistor in the emitter of the driver device requires about 7.0mA before the output switch conducts.

Representative Schematic Diagram

1.25V

Reference

Regulator

Ipk

Oscillator

CT

R

SQ

Q2

Q1

100

Comparator

+

_

(Bottom View)

8

7

6

5

1

2

3

4

Gnd

Timing

Capacitor

Switch

Emitter

Switch

Collector

Drive

Collector

Sense

Comparator

Inverting

Input