CMOS CURRENT MODE
PWM CONTROLLER
1
2
3
4
5
6
7
8
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.)
VOH
VOL
tR
Output High Level
ISOURCE = 20mA
ISOURCE = 100mA
CL = 1000pF
VDD – 1V
VDD – 4V
V
Output High Level
Output Rise Time
Output Fall Time
V
50
50
150
150
nsec
nsec
tF
CL = 1000pF
Undervoltage Lockout
Start-Up
Threshold
7.15
0.5
7.7
8.25
1
V
V
Threshold Hysteresis
0.75
Supply
IS Standby Supply Current
2.7
3.8
mA
PIN DESCRIPTION
Pin No.
(16-Pin PDIP)
Symbol
Description
1
SOFT START/ILIM Soft Start Adjust / Current Limit. For setting the peak current threshold of sense inputs (pins
3 and 4). Second function of this pin is Soft-Start Adjust.
2
3
VREF OUT
– ISENSE IN
Reference supply output of 5.1 volts. It can supply a minimum of 10mA.
– Current Sense Input. Inverting input for sensing peak current of the pass transistor
through series sense current monitor resistor.
4
+ ISENSE IN
+ Current Sense Input. Non-inverting input used in conjunction with pin 3. This senses the
positive end of current monitor resistor.
5
6
7
8
+ ERROR AMP IN + Error Amp In. Non-inverting input for output voltage regulation.
– ERROR AMP IN – Error Amp In. Inverting input of the amplifier for the reference voltage.
CMPTR
CO
For compensation of the feedback loop response.
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.
9
RO
Timing resistor (RO) input to set oscillator frequency by setting constant current charge rate
to charge capacitor CO.
10
SYNC
For PWM controller oscillator synchronization of two or more controllers. or as a clock input
to sync oscillator from external signal.
11
12
13
14
15
16
OUTPUT A
GND
A output drive of phase A from push pull transistors.
Ground return for all input and output pins.
VDD
Supplies power to operate the output drivers only.
Output of phase B from push pull transistors.
OUTPUT B
VIN
Voltage bias supply for all TC170 circuits except the output transistors.
Input pin to disable both output drives to 0V OFF.
SHUTDOWN
PIN CONFIGURATIONS (DIP and SOIC)
SOFT START/
C
SHDN
1
2
3
4
5
6
7
8
16
15
14
13
V
I
INT
1
2
3
4
5
16
15
14
LIM
DD
V
OUT
IN
V
V
DIGITAL GND
REF
IN
SS
AZ
C
– I
+ I
SENSE
SENSE
OUTPUT B
CMPTR OUT
IN
V
BUF
B
A
DD
13
12
11
10
TC170
CPE
TC170COE
+ ERROR AMP IN
– ERROR AMP IN
CMPTR
12 GND
11
ACOM
–
+
C
V
OUTPUT A
10 SYNC
REF
6
7
8
IN
+
–
C
V
REF
IN
+
–
C
O
R
9
V
V
O
9
REF
REF
NOTE: Outputs LOW in "OFF" state.
TELCOM SEMICONDUCTOR, INC.
4-121
TELCOM [ TELCOM SEMICONDUCTOR, INC ]
