TelCom Semiconductor Inc TC170CPE, TC170COE Datasheet
CMOS CURRENT MODE PWM CONTROLLER
1
TC170
FEATURES
■ Low Supply Current With
CMOS Technology................................. 3.8mA Max
■ Internal Reference .............................................5.1V
■ Fast Rise/Fall Times (CL = 1000pF) ............. 50nsec
■ Dual Push-Pull Outputs
■ Direct-Power MOSFET Drive
■ High Totem-Pole Output Drive .................... 300mA
■ Differential Current-Sense Amplifier
■ Programmable Current Limit
■ Soft-Start Operation
■ Double-Pulse Suppression
■ Undervoltage Lockout
■ Wide Supply Voltage Operation ...............8V to16V
■ High Frequency Operation ..........................200kHz
■ Available with Low OFF State Outputs
■ Low Power, Pin-Compatible Replacement for UC3846
ORDERING INFORMATION
Temperature
Part No. Package Range
TC170COE 16-Pin SOIC (Wide) 0°C to +70°C
TC170CPE 16-Pin Plastic DIP (Narrow) 0°C to +70°C
GENERAL DESCRIPTION
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.
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
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 component count. The TC170 is pin compatible with the Unitrode
UC1846/2846/3846 bipolar controller.
Other advantages inherent in current-mode control include superior line and load regulation and automatic symmetry correction in push-pull converters.
2
3
4
5
FUNCTIONAL BLOCK DIAGRAM
15
V
IN
9
R
C
SYNC
(–) CURRENT
SENSE INPUT
(+) CURRENT
SENSE INPUT
COMP
(+) ERROR
AMP INPUT
(–) ERROR
AMP INPUT
O
O
8
10
3
4
7
5
6
OSCILLATOR
× 3.15 CURRENT
AMPLIFIER
–
+
V
DD
100µA
+
–
ERROR
AMPLIFIER
TELCOM SEMICONDUCTOR, INC.
–
0.75V
LOCK-UP
AMPLIFIER
Q3
PWM
COMPARATOR
+
+
–
LIMIT BUFFER
AMPLIFIER
350mV
REFERENCE
UNDERVOLTAGE
+
–
Q4
–
+
POSITIVE
FEEDBACK
5.1-VOLT
LOCKOUT
R
S
S
Q
PWM LATCH
Q1
V
REF
Q2
3.5kΩ
2
TC170
DQ
C
Q
SHUTDOWN
COMPARATOR
+
350
–
mV
6kΩ
1
CURRENT LIMIT/
SOFT-START ADJUST
16
SHUTDOWN
NOTE: Outputs low in
OFF state.
13
11
14
12
V
DD
OUTPUT
A ( )
OUTPUT
B ( )
GROUND
6
7
8
TC170-5 10/1/96
4-119
TC170
CMOS CURRENT MODE
PWM CONTROLLER
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage ............................................................18V
Output Voltage ................................................ VDD or 18V
Analog Inputs .....................................– 0.3V to VS + 0.3V
Storage Temperature Range ................ – 65°C to +150°C
Lead Temperature (Soldering, 10 sec) ................. +300°C
Maximum Chip Temperature...................................150°C
Plastic Package Thermal Resistance:
θJA (Junction to Ambient)............................. 140°C/W
Operating Temperature Range
Commercial ...........................................0°C to +70°C
*Static-sensitive device. Unused devices must be stored in conductive
material. Protect devices from static discharge and static fields. Stresses
above those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only and functional
operation of the device at these or any other conditions above those
indicated in the operational sections of the specifications is not implied.
Exposure to Absolute Maximum Rating Conditions for extended periods
may affect device reliability.
θJC (Junction to Case) ................................... 70°C/W
ELECTRICAL CHARACTERISTICS: V
= 16V, RO = 24kΩ, CO = 1 nF, TA = 25°C, unless otherwise indicated.
IN
Symbol Parameter Test Conditions Min Typ Max Unit
Reference Voltage
V
V
REF
RTC
Output Voltage I
= 1mA 5 5.1 5.3 V
OUT
Line Regulation VIN = 8V to 16V 5 15 mV
Load Regulation I
= 1mA to 10mA 13 20 mV
OUT
Temperature Coefficient Over Operating Temperature Range 0.4 0.5 mV/°C
Oscillator
Oscillator Frequency 35 42 46 kHz
Voltage Stability VIN = 8V to 16V 1.1 1.5 %/V
Temperature Stability Over Operating Temperature Range 5 10 %
Error Amplifier
V
OS
I
B
V
CMRR
A
VOL
BW Unity Gain Bandwidth 1.2 MHz
CMRR Common-Mode Rejection Ratio V
PSRR Power Supply Rejection Ratio VIN = 8V to 16V 60 dB
Input Offset Voltage 630 mV
Input Bias Current 61nA
Common-Mode Input Voltage VIN = 8V to 16V 0 V
Open-Loop Voltage Gain V
= 1V to 6V 70 dB
OUT
0V to 14V 60 dB
CMV
– 2V V
DD
Current Sense Amplifier
Amplifier Gain Pin 3 = 0V to 1.1V 3 3.15 3.3 V/V
Maximum Differential Input Signal V
Common-Mode Input Voltage 0 V
PIN4
– V
PIN3
≤1.1 V
– 3V V
DD
Current Limit Adjust
Current Limit Offset Voltage 0.5 1 V
I
B
Input Bias Current 1nA
Shutdown Terminal
V
TB
V
IN
Threshold Voltage 0.3 0.35 0.4 V
Input Voltage Range 0 V
DD
V
Minimum Latching Current at Pin 1 125 µA
Maximum Nonlatching Current at Pin 1 50 µA
Output Stage
V
DD
V
OL
V
OL
Output Voltage Pin 13 V
Output Low Level I
Output Low Level I
= 20mA 0.4 V
SINK
= 100mA 2 V
SINK
– 0. 5 V
IN
V
IN
+ 0.5 V
IN
4-120
TELCOM SEMICONDUCTOR, INC.
CMOS CURRENT MODE
PWM CONTROLLER
1
TC170
ELECTRICAL CHARACTERISTICS (Cont.):
VIN = 16V, RO = 24kΩ, CO = 1nF, TA = 25°C, unless otherwise indicated.
Symbol Parameter Test Conditions Min Typ Max Unit
Output Stage (Cont.)
V
OH
V
OL
t
R
t
F
Output High Level I
Output High Level I
= 20mA V
SOURCE
= 100mA V
SOURCE
– 1V V
DD
– 4V V
DD
Output Rise Time CL = 1000pF 50 150 nsec
Output Fall Time CL = 1000pF 50 150 nsec
Undervoltage Lockout
Start-Up Threshold 7.15 7.7 8.25 V
Threshold Hysteresis 0.5 0.75 1 V
Supply
ISStandby Supply Current 2.7 3.8 mA
PIN DESCRIPTION
Pin No.
(16-Pin PDIP) Symbol Description
1 SOFT START/I
2V
3– I
4+ I
OUT Reference supply output of 5.1 volts. It can supply a minimum of 10mA.
REF
IN – Current Sense Input. Inverting input for sensing peak current of the pass transistor
SENSE
IN + Current Sense Input. Non-inverting input used in conjunction with pin 3. This senses the
SENSE
5 + ERROR AMP IN + Error Amp In. Non-inverting input for output voltage regulation.
6 – ERROR AMP IN – Error Amp In. Inverting input of the amplifier for the reference voltage.
7 CMPTR For compensation of the feedback loop response.
8C
9R
O
O
10 SYNC For PWM controller oscillator synchronization of two or more controllers. or as a clock input
11 OUTPUT A A output drive of phase A from push pull transistors.
12 GND Ground return for all input and output pins.
13 V
DD
14 OUTPUT B Output of phase B from push pull transistors.
15 V
IN
16 SHUTDOWN Input pin to disable both output drives to 0V OFF.
Soft Start Adjust / Current Limit. For setting the peak current threshold of sense inputs (pins
LIM
3 and 4). Second function of this pin is Soft-Start Adjust.
through series sense current monitor resistor.
positive end of current monitor resistor.
Timing capacitor (CO) input to set oscillator frequency in conjunction with pin 9, RO, resistor
input. Second function is for setting crossover dead time of pin 11and 14 outputs.
Timing resistor (RO) input to set oscillator frequency by setting constant current charge rate
to charge capacitor CO.
to sync oscillator from external signal.
Supplies power to operate the output drivers only.
Voltage bias supply for all TC170 circuits except the output transistors.
2
3
4
5
6
PIN CONFIGURATIONS (DIP and SOIC)
SOFT START/
I
LIM
OUT
V
REF
– I
SENSE
+ I
SENSE
+ ERROR AMP IN
– ERROR AMP IN
CMPTR
C
1
2
IN
3
IN
4
TC170
5
CPE
6
7
8
O
SHDN
16
V
15
14
OUTPUT B
V
13
12
GND
11
OUTPUT A
10
SYNC
R
9
IN
DD
O
TELCOM SEMICONDUCTOR, INC.
C
INT
V
SS
C
AZ
BUF
ACOM
–
C
REF
+
C
REF
–
V
REF
1
2
3
4
TC170COE
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
DIGITAL GND
CMPTR OUT
B
A
+
V
IN
–
V
IN
+
V
REF
NOTE: Outputs LOW in "OFF" state.
7
8
4-121
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