onsemi | TL494CDR2G

The TL494 is a fixed frequency, pulse width modulation control circuit designed primarily for SWITCHMODE power supply control.

The TL494 incorporates all the functions required in the construction of a pulse-width-modulation (PWM) control circuit on a single chip. Designed primarily for power-supply control, this device offers the flexibility to tailor the power-supply control circuitry to a specific application.  The TL494 contains two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, a 5-V, 5%-precision regulator, and output-control circuits. The error amplifiers exhibit a common-mode voltage range from -0.3 V to VCC -2 V. The dead-time control comparator has a fixed offset that provides approximately 5% dead time. The on-chip oscillator can be bypassed by terminating RT to the reference output and providing a sawtooth input to CT, or it can drive the common circuits in synchronous multiple-rail power supplies.

The uncommitted output transistors provide either common-emitter or emitter-follower output capability. The TL494 provides for push-pull or single-ended output operation, which can be selected through the output-control function. The architecture of this device prohibits the possibility of either output being pulsed twice during push-pull operation. The TL494C is characterized for operation from 0C to 70C. The TL494I is characterized for operation from -40C to 85C. The TL494B is characterized for operation from -40C to 125C. The NCV494B is characterized for -40C to 125C and certified for automotive applications.

Key Features:

• Complete Pulse Width Modulation Control Circuitry
• On−Chip Oscillator with Master or Slave Operation
• On−Chip Error Amplifiers
• On−Chip 5.0 V Reference
• Adjustable Deadtime Control
• Uncommitted Output Transistors Rated to 500 mA Source or Sink
• Output Control for Push−Pull or Single−Ended Operation
• Undervoltage Lockout
• NCV Prefix for Automotive and Other Applications Requiring Site and Control Changes
• Pb−Free Packages are Available

Benefits:

• Optimize system size and efficiency
• Simple to use in buck configuration

Applications:

• Off-line power supply
• Buck converter
• LED Lighting
• VPA (Vehicle Power Adapter)