TL494 LINEAR INTEGRATED CIRCUIT
1
VOLTAGE MODE PWM CONTROL
CIRCUIT
DESCRIPTION
The Contek TL494 incorporates all the functions required in
the construction of a pulse-width modulation switching circuit.
Designed primarily for switching power supply control or DC-
DC convectors, it offers the systems engineer the flexibility to
tailor control circuitry to its own application.
FEATURES
*Complete PWM power control circuitry
*Uncommitted outputs for 200 mA sink or source current
*Output control selects single ended or push pull operation
*Internal circuitry prohibits double pulses over total range
*Easy synchronization
DIP-16
SOP-16
ABSOLUTE MAXIMUM RATINGS(Unless otherwise noted all is over operating free air temperature
range)
PARAMETER SYMBOL VALUE UNIT
Supply Voltage(note 1) VCC 41 V
Amplifier Input Voltage VIVCC+0.3 V
Collector Output Voltage VO41 V
Collector Output Current ICO 250 mA
Continuous Total Dissipation at(or for below)
25 C Free Air Temperature(note 2)
PD1000 mW
Operating Temperature Range Topr 0TO70 C
Storage Temperature Range Tstg -65 TO 150 C
Lead Temperature 1.6mm from Case for 60
Sec.
Tcase 300 C
note 1: All voltage values, except differential voltages are with respect to the network ground terminal.
note 2:For operation above 25 C free-air temperature, the dissipation derates with 9.2mW/ C.
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL494 LINEAR INTEGRATED CIRCUIT
2
BLOCK DIAGRAM
Error
Amplifier
Error
Amplifier
dead time
control
dead time comparator
oscillator
Pulse Steering
Flip-Flop
Input
control
5V reference
regulation
Vref
Vcc
GND
PWM comparator
0.7mA
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
T
Q
Q
Q1
Q2
RT
CT
C1
E1
C2
E2
RECOMMENDED OPERATING CONDITIONS
PARAMETER SYMBOL VALUE UNIT
MIN MAX
Supply Voltage Vcc 7 40 V
Amplifier Input Voltage Vi -0.3 Vcc-2 V
Collector Output Voltage Vo 40 V
Collector Output Current(each Transistor) Ic 200 mA
Current into Feedback If0.3 mA
Timing Capacitor CT0.47 10000 nF
Timing Resistor RT1.8 500 kW
Oscillator Frequency fosc 1 300 kHz
Operating Free-Air Temperature Ta 0 70 C
ELECTRICAL CHARACTERISTICS
(Over recommended operating free-air temperature range,VCC=15V,f=1kHz,Unless otherwise specified)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Reference Section
Output Voltage Io=1mA 4.75 5 5.25 V
Input Regulation Vcc=7V to 40V 2 25 mV
Output Regulation Io=1 to 10mA 1 15 mV
Output Voltage Change with
Temperature
DTA=MIN to MAX(note 2) 0.2 1 %
Short-Circuit Output Current Vref=0 35 mA
Oscillator Section
Frequency CT=0.01mF,R T=120kW10 kHz
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL494 LINEAR INTEGRATED CIRCUIT
3
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Standard Deviation of Frequency All Values of Vcc CT,RT,TA
constant
10 %
Frequency Change with Voltage Vcc=7v to 40V,Ta=25 C 0.1 %
Frequency Change with
Temperature
CT=0.01mF,R T=12kW,DTA=MIN
to MAX
12 %
Amplifier Section
Input Offset Voltage Error Vo(pin 3)=2.5V 2 10 mV
Input Offset Current Vo(pin 3)=2.5V 25 250 nA
Input Bias Current Vo(pin 3)=2.5V 0.2 1 mA
Common-Mode Input Voltage
Range
Error Vcc=7V to 40 V -0.3 to
Vcc-2
V
Open-Loop Voltage Amplification DVo=3V, Vo=0.5V to 3.5V 70 95 dB
Unity-Gain Bandwidth 800 kHz
Common-Mode Rejection Ratio Error Vcc=40V,T A=25 C 65 80 dB
Output Sink Current(pin 3) VID=-15mV to -5V
V(pin 3)=0.5V
0.3 0.7 mA
Output source Current(pin 3) VID=15mV to -5V V(pin 3)=3.5V -2 mA
Output Section
Collector off-state current VCE=40V,Vcc=40V 2 100 mA
Emitter off-state Current VCC=VC=40V,VE=0 -100 mA
Collector -emitter Saturation
Voltage
Common-
emitter
VE=0,Ic=200mA 1.1 1.3 V
Emitter-
Follower
Vc=15V,I E=-200mA 1.5 2.5
Output Control Input Current Vi=Vref 3.5 mA
Dead Time Control Section
Input bias (pin 4) Vi=0 to 5.25V -2 -10 mA
Maximum duty cycle, each output VI(pin 40=0 45 %
Input threshold Voltage(pin 4) Zero duty Cycle 3 3.3 V
Maximum duty cycle 0
PWM comparator Section
Input Threshold Voltage(pin 3) Zero Duty cycle 4 4.5 V
Input Sink Current (pin 3) Vpin 3= 0.7V 0.3 0.7 mA
Total Device
Standby Supply Current Vcc=15V pin 6 at Vref,all other Inputs and
outputs open 6
10 mA
Vcc=40V 9 15
Average supply current Vpin 4=2V 7.5 mA
Switching Characteristics,Ta=25 C
Output Voltage Rise Time Common-emitter configuration 100 200 ns
Output Voltage Fall Time 25 100 ns
Output Voltage Rise Time Emitter-follower configuration 100 200 ns
Output Voltage Fall Time 40 100 ns
note 1:All typical Values except for temperature coefficient are at Ta=25 C.
note 2:For conditions shown as MIN or MAX, use appropriate value under recommended operating conditions.
note 3:Duration of the short-circuit should not exceed one second.
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL494 LINEAR INTEGRATED CIRCUIT
4
note 4: Standard deviation is a measure of the statistical distribution the mean as derived from the formula :
TEST CIRCUIT
DEAD-TIME
FEEDBACK
RT
CT
ERROR AMPLIFIER
OUTPUT CONTROL
GND
E2
C2
E1
C1
Vcc
TEST
INPUTS
1
2
3
4
5
6
7
8
9
10
11
12
14
15
16
13
Vcc=15V
2W 150 W2W 150 W
OUTPUT 1
OUTPUT 2
Vref
OUTPUT
50kW
12kW
0.01 mF
VOLTAGE
at C1
DEAD-TIME
CONTROL INPUT
FEEDBACK
VOLTAGE
at C2
VOLTAGE
at CT
THRESHOLD VOLTAGE
THRESHOLD VOLTAGE
FIG 1. OPERATIONAL TEST CIRCUIT AND WAVEFORMS
s=S
N
(xn-x)
2
N-1
n=1
Contek
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL494 LINEAR INTEGRATED CIRCUIT
5
Vin
ERROR
AMPLIFIER
1
2
15
16
Vref
ERROR
AMPLIFIER
FEEDBACK
TERMINAL
FIG 2. AMPLIFIER CHARACTERISTICS
15pF
68W
Q
EACH
OUTPUT
CIRCUIT
Vcc
tr tf
90%
10%
90%
10%
Vc
15pF68W
Q
EACH
OUTPUT
CIRCUIT
Vcc
tr tf
90%
10%
90%
10%
Ve
FIG. 3 COMMON-EMITTER CONFIGURATION FIG. 4 EMITTER -FOLLOWER CONFIGURATION
PIN CONFIGURATIONS
1
2
3
4
5
6
7
89
10
11
12
13
14
15
16
NONINV
INPUT
INV INPUT
FEEDBACK
DEAD-TIME
CONTROL
CT
RT
GND
C1 E1
E2
C2
OUTPUT
CONTROL
Vcc
Vref
INV INPUT
NONINV
INPUT
Contek
TL494
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com
TL494 LINEAR INTEGRATED CIRCUIT
6
TYPICAL PERFORMANCE CHARACTERISTICS
6
10
5
10
4
10103
2
10
1
10
103
4
10
5
10 Vcc=15V
Ta=0~70 XC
CT=0.001 mF
CT=0.01 mF
CT=0.1 mF
CT=1 mF
RT(Timing Resistance) ( W)
Oscillator Frequency (Hz)
6
10
5
10
4
101032
10
0
20
40
60
80
100
Vcc=15V
DV=3V
Ta=25 XC
Voltage Amplification (dB)
Frequency (Hz)
FIG 5. Oscillator Frequency and Frequency Variation Fig.6 Amplifier Voltage Amplification
Vs
Timing Resistance
CONTEK
Contek Microelectronics Co.,Ltd.
http://www.contek-ic.com E-mail:sales@contek-ic.com