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Revision 1, May 2002
www.gammamicro.com
1.5A DC-to-DC CONVERTER CONTROL CIRCUIT
GM34063
PRELIMINARY
1
3.0V to 40V input
Adjustable Output Voltage
Current Limiting
Output Switch Current to 1.5A
Low Standby Current
Operating Frequency to 100kHz
Precision 2% Reference
The GM34063 has all the functions required for
DC-to-DC converters: an internal temperature-
compensated reference, comparator, controlled
duty cycle oscillator with an active current limit
circuit, driver, and high-current output switch.
The 34063 designed for step-down, step-up and
voltage-inverting applications using a minimum
number of external components.
SCHEMATIC DIAGRAM
PIN CONNECTIONS
CD-ROM
Motherboards
SMPS Power Supply
Battery Chargers
Applications:
1
2
3
4
8
7
6
5
Switch
Collector
Driver
Collector
Switch Emitter
Timing
Capacitor
GND
I
pk Sense
V
CC
Comparator
Inverting unit
(Top View)
8
7
6
5
4
3
2
1
Driver Collector
I
pk Sense
V
CC
Comparator
Inverting unit
GND
Timing Capacitor
Switch Emitter
Switch Collector
(Bottom View)
S
R
QQ2
Q1
100
Comparator
+
-
1.25V
Reference
Regulator
I
pk Oscillator
C
T
* The GM34063 has 51 active transistors on-chip.