PJ494 Datasheet, PDF (1/11 Pages) List of Unclassifed Manufacturers – Switchmode Pulse Width Modulation Control Circuit

PJ494
Switchmode Pulse Width Modulation Control Circuit
T he PJ494 incorporates on a single monolithic chip all
the functions required in the construction of a pulse-
width-modulation control circuit. Designed primarily for
power supply control, these devices offer the systems
engineer the flexibility to tailor the power supply control
circuitry to his application.
The PJ494 contains an error amplifier, an on-chip adjustable
oscillator, a deed-time control comparator, pulse-steering
control flip-flop, a 5-volt, 5% precision regulator, and output-
control circuits. The error amplifier exhibits a common-mode
voltage from –0.3 volts to Vcc –2 volts. The dead-time
control comparator has a fixed offset that provides
approximately 5% dead time when externally altered. The on-
chip oscillatory be bypassed by terminating R_T (pin 6) to the
reference output and providing a sawtooth input to C_T (PIN
5), or it may be used to drive the common circuits in
synchronous multiple-rail power supplies. The uncommited
output transistor provide either common-emitter or emitter-
follower output capability. Each device provides for push-pull
or single-ended output operation, which may be selected
through the output-control function. The architecture of these
devices prohibits the possibility of either output being pulsed
twice during push-pull operation.
FEATURES
• Complete PWM Power Control Circuitry
• Uncommitted Outputs for 200mA Sink or Source Current
• Output Control Selects Single-Ended or Push –Pull Operation
• Internal Circuitry Prohibits Double Pulse at Either Output
• Variable Dead-Time Provides Control over Total Range
• Internal Regulator Provides a Stable 5-V Reference Supply, 5%
• Circuit Architecture Allows Easy Synchronization
ORDERING INFORMATION
Device
PJ494CD
PJ494CS
OperatingTemperature
(Ambient)
-20℃ to +85℃
Package
DIP-16
SOP-16
DIP-16
SOP-16
Pin 1.Noninv Input
2.Inv Input
3.Feedback
5.C_T
8.C1
11.C2
13.Output Control
15. Inv Input
16. Noninv Input
﹜Error Amp1
4.Dead-Time Control
6.R_T
9.E1
7.Gnd
10.E2
12.Vcc
14.Ref Out
﹜Error Amp2
ABSOLUTE MAXIMUM RATINGS OVER OPERATING FREE-AIR TEMPERATURE RANGE
(unless otherwise noted)
Rating
Symbol
Value
Unit
Supply voltage
Vcc
41
V
Amplifier input voltage
Vi
Vcc+0.3
Collector output voltage
Vo
41
Collector output current
250
mA
Operating free-air temperature range
-20 to 85
Storage temperature range
Operating Junction Temperature
T_stg
-25 to 125
℃
TJ
125
Lead temperature 1,6mm from case for 10 seconds
260
Power Dissipation @TA≦45℃
PD
1000
mW
1-11
2002/11.rev.A