ML4826
TYPICAL PERFORMANCE CHARACTERISTICS
250
250
200
200
Transconductance (µ )
Ω
Transconductance (µ )
Voltage Error Amplifier (VEA) Transconductance (g
m
)
400
Variable Gain Block Constant - K
Ω
150
100
50
0
0
1
2
VFB (V)
3
4
5
300
200
100
0
0
1
2
3
VRMS (mV)
20
VEAO
VFB
19
2.5V
IAC
2
VRMS
4
ISENSE
3
RAMP 1
8
RTCT
7
OSCILLATOR
x2
GAIN
MODULATOR
3.5kΩ
-
+
+
-
150
100
50
0
-500
0
IEA Input Voltage (mV)
500
Current Error Amplifier (IEA) Transconductance (g
m
)
4
5
Variable Gain Control Transfer Characteristic
1
IEAO
OVP
+
+
17
VCCZ
13.5V
VCC
7.5V
REFERENCE
S
-1V
+
-
VEA
3.5kΩ
-
IEA
2.7V
VREF
18
-
Q
Q
PFC OUT
Q
Q
15
8V
R
S
R
PFC ILIMIT
VCCZ
UVLO
Figure 1. PFC Section Block Diagram.
6