TC170 Datasheet, PDF (1/8 Pages) TelCom Semiconductor, Inc – CMOS CURRENT MODE PWM CONTROLLER

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TC170
CMOS CURRENT MODE PWM CONTROLLER
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FEATURES
GENERAL DESCRIPTION
s Low Supply Current With
CMOS Technology ................................. 3.8mA Max
s Internal Reference ............................................. 5.1V
s Fast Rise/Fall Times (C_L = 1000pF) ............. 50nsec
s Dual Push-Pull Outputs
s Direct-Power MOSFET Drive
s High Totem-Pole Output Drive .................... 300mA
s Differential Current-Sense Amplifier
s Programmable Current Limit
s Soft-Start Operation
s Double-Pulse Suppression
s Undervoltage Lockout
s Wide Supply Voltage Operation ............... 8V to16V
s High Frequency Operation .......................... 200kHz
s Available with Low OFF State Outputs
s Low Power, Pin-Compatible Replacement for UC3846
ORDERING INFORMATION
Part No.
TC170COE
TC170CPE
Package
Temperature
Range
16-Pin SOIC (Wide)
0°C to +70°C
16-Pin Plastic DIP (Narrow) 0°C to +70°C
The TC170 brings low-power CMOS technology to the
current-mode-switching power supply controller market.
Maximum supply current is 3.8 mA. Bipolar current-mode
control integrated circuits require five times more operating
current.
3 ^{The dual totem-pole CMOS outputs drive power}
MOSFETs or bipolar transistors. The 50nsec typical output
rise and fall times (1000pF capacitive loads) minimize
MOSFET power dissipation. Output peak current is 300mA.
The TC170 contains a full array of system-protection
circuits (see features).
Current-mode control lets users parallel power supply
modules. Two or more TC170 controllers can be slaved
4 ^{together for parallel operation. Circuits can operate from a}
master TC170 internal oscillator or an external system
oscillator.
The TC170 operates from an 8V to 16V power supply.
An internal 2%, 5.1V reference minimizes external compo-
nent count. The TC170 is pin compatible with the Unitrode
UC1846/2846/3846 bipolar controller.
Other advantages inherent in current-mode control in-
5 ^{clude superior line and load regulation and automatic sym-}
metry correction in push-pull converters.
FUNCTIONAL BLOCK DIAGRAM
VREF
2
VIN ¹⁵
RO ⁹
CO ⁸
10
SYNC
(–) CURRENT 3
SENSE INPUT
(+) CURRENT ⁴
SENSE INPUT
7
COMP
(+) ERROR 5
AMP INPUT
(–) ERROR 6
AMP INPUT
OSCILLATOR
5.1-VOLT
REFERENCE
UNDERVOLTAGE
LOCKOUT
TC170
13 _VDD
11
OUTPUT
A( )
–
× 3.15 CURRENT
AMPLIFIER
PWM
–+
COMPARATOR
+
+
0.75V
–
VDD
100µA
+
LIMIT BUFFER
AMPLIFIER
R
Q
S
DQ
C
Q
S
PWM LATCH
–
Q4
ERROR
AMPLIFIER
350mV
LOCK-UP
AMPLIFIER
Q3
–
+
POSITIVE
FEEDBACK
SHUTDOWN
COMPARATOR
Q1 Q2
3.5k Ω
350
mV
6k Ω
14 OUTPUT
B( )
12
GROUND
1 _{CURRENT LIMIT/}
SOFT-START ADJUST
16
SHUTDOWN
NOTE: Outputs low in
OFF state.
TELCOM SEMICONDUCTOR, INC.
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TC170-5 10/1/96
4-119
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