Service manual

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IC851(TL1451) is a 2-way PWM control IC.
C851/R851 determine the frequency of PWM.
Pin 1IN+/1IN- and 2IN+/2IN- are the inputs of the error amplifiers. 1IN+/2IN+ are used as the
feedback pins for DC-DC circuit.
1DTC/2DTC are used for determining the threshold states of dead time control.
C854, C855, C857, C858, R855 and R873 are used for gain/phase compensation.
R855
47K
R873
47K
R851
10K F
R859
10K F
R857
10K F
R853
10K F
R854
10K F
IC851
TL1451ACN
CT
1
RT
2
1IN +
3
1IN -
4
1FBK
5
1DT C
6
1OUT
7
GND
8
VCC
9
2OUT
10
2DT C
11
2FBK
12
2IN-
13
2IN+
14
SCP
15
RFF
16
R858
330K
C855
0.01U K
C858
0.01U K
C852
0.1U K
C851
470P K
R863
330
P11
C857
220P K
C854
220P K
R856
330K
C853
1U M
C856
1U M
C859
1U M
P13
V-INVERTER
F851
32V 2A
The timing diagram of TL1451 is shown as following: