Datasheet
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G001
Power
Supply#1
bqHYBRID
EVM
VBAT
I
o
R
36
L
0.25W
W
5
50W
W
SYS
AC
EN
Power
Supply#2
Current
Meter
B0235-03
PROCEDURE
voltage of power supply #2 slowly to 4.2 V. Disconnect J6 pin 1 (EN) from pin 2 (DC–). Make J6 pin 1
(EN) open. Verify the voltage across R
L
(SYS to DC–) is regulated between 1.75 V and 1.85 V. Verify
the voltage at the SW pin, or terminal 1 of L1, is like that shown in Figure 2-3 . Verify that its frequency
is about 1 MHz and the duty cycle is stable at some value between 0.38 and 0.5.
Figure 2-3. Waveform at Pin SW
10. DC-DC Converter Under Light-Load Condition (bq25012 as an Example). Change R
L
to the 36- Ω ,
0.25-W resistor. Make sure the setup has been changed to that shown in Figure 2-4 . Verify the voltage
across R
L
(SYS to DC–) is regulated between 1.75 V and 1.85 V. Verify the voltage at the SW pin, or
terminal 1 of L1, is like that shown in Figure 2-5 . Verify that its frequency is about 1 MHz and the duty
cycle is stable at some value between 0.38 and 0.5.
Figure 2-4. Test Setup C
SLUU214A – December 2004 – Revised June 2007 Basic Functions Evaluation 9
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