Page 60 - GIGABYTE Service Manual-v3.0-110101

3.2.6 VCC1_5 and 2_5LEVEL, 1_5LEVEL

VCC1_5 circuit is separated into 4 sections:
A. MOSFET
B. Low Power Quad Operational Amplifiers

C. Feedback circuit
D. Over Voltage Controller

Figure 3-13: VCC1_5 circuit

MOSFET Section:
The section Includes Q61 and R, C. The output VCC1_5 (1.5V) depends on input
DDR18V and control gate which input from U18. If control gate fail, we can measure
the voltage across resistor R373 to confirm any resistor broken or U18 pin8 fail. Also

need to measure impedance on pin 1 of Q61.
Low Power Quad Operational Amplifiers Section:
The section Includes U18 and R, C. The output pin 8 depends on pin 9, 10 which pin 10
inputs from 1_5LEVEL and divided voltage of 2_5LEVEL, and pin 9 feedback circuits,

over voltage circuit 1_5_OV.
Feedback circuit Section:
The section Includes R449, R450 and C252, EC17. For the feedback pin 9, we can read
a voltage of 1.5V. This pin also connects to 1_5_OV for over voltage from U15.

Over Voltage Controller Section:
The section Includes U15 which is three voltage channels Console. The uP6262 is a
high precision voltage console consisting of three sets I2C programmable current
DACs.

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