TC170 Datasheet, PDF (7/16 Pages) TelCom Semiconductor, Inc – CMOS CURRENT MODE PWM CONTROLLER

TC170
FIGURE 3-1:
R1 AND R2 SET MAXIMUM PEAK OUTPUT CURRENT
Switch
Current
x 3.15 Current Sense
Amplifier
4
+
3
RS
–
–+
0.75V
7
PWM Comparator
+
–
Error
Amplifier
5
+
6
–
V_DD
100µA
Q4
V1
Limit
Buffer
Amplifier
From
Undervoltage
Lockout
10
R
SQ
"A" = 1
Output
Off (Low)
S
PWM Latch
V_REF
5.1V
2
R1
1
V1
R2
Q3
350mV
TC170
Lock-Up
Amplifier
–
Q1
Q2
+ _Positive
Feedback
I_L
3.5kΩ
Shutdown
Comparator
350mV
16
6kΩ
FIGURE 3-2:
GROUND REFERENCE
RESISTIVE SENSING
x 3.15 Current Sense
Amplifier
4
I
R*
C
RS
3
TC170
*Optional RC Filter
FIGURE 3-3:
I
x 3.15 Current Sense
Amplifier
ABOVE GROUND
RESISTIVE SENSING
RS
V_OUT
4
3
TC170
© 2002 Microchip Technology Inc.
DS21395B-page 7