The KA7500BD is a comprehensive fixed-frequency PWM control circuit containing all the functions required for the construction of switch-mode power supplies (SMPS). It is functionally equivalent to the industry-standard TL494. This IC is widely used in PC power supplies, DC-DC converters, and motor control systems due to its ability to drive two internal power transistors in either push-pull or single-ended configurations.

Specifications

• Supply Voltage (Vcc): 7V to 40V
• Output Current: 200mA (Collector Output Current)
• Oscillator Frequency: 1kHz to 300kHz
• Internal Reference Voltage: 5.0V (± 5%)
• Dead-Time Control Range: 0% to 100%
• Package: DIP-16 (Dual In-line Package)

Features

• Complete PWM Power Control Circuit: Includes an on-chip oscillator, two error amplifiers, a pulse-steering flip-flop, and an adjustable dead-time control.
• Uncommitted Output Transistors: The internal output transistors provide either common-emitter or emitter-follower output capability, offering flexibility for different circuit topologies.
• Output Control Pin: A dedicated pin allows for the selection of single-ended or push-pull operation.
• Precision Reference: Provides a stable 5V internal reference voltage to simplify external circuitry.
• Dead-Time Adjustment: Prevents "shoot-through" currents in push-pull configurations by providing a controllable dead-time between output pulses.

Common Applications

• ATX PC Power Supplies: Managing the primary voltage rails.
• DC-DC Buck/Boost Converters: Providing regulated power for industrial equipment.
• Inverters: Converting DC battery power to AC.
• Motor Speed Control: Utilizing PWM to efficiently control DC motor speed.

Usage Tips

• Oscillator Setup: The frequency is determined by the formula F = 1.1/Rt x Ct
• Output Mode: Connect the Output Ctrl (Pin 13) to REF (Pin 14) for push-pull operation, or to GND (Pin 7) for single-ended/parallel operation.
• Protection: Use the second error amplifier for over-voltage or over-current protection by comparing a sense voltage against the 5V reference.
• Heat Dissipation: While the IC handles the logic, ensure the external power MOSFETs or BJTs it drives are properly heatsinked for high-power applications.

Datasheet