Overview
The TL494BD, produced by onsemi, is a fixed-frequency pulse-width-modulation (PWM) control circuit designed primarily for switch mode power supply control. This integrated circuit incorporates all the necessary functions for constructing a PWM control circuit on a single chip, making it highly versatile for various power supply applications. The TL494BD features an on-chip oscillator, error amplifiers, a 5.0 V reference voltage, and adjustable dead-time control, among other key functionalities.
Key Specifications
| Characteristics | Symbol | Min | Typ | Max | Unit |
|---|---|---|---|---|---|
| Power Supply Voltage | VCC | 7.0 | 15 | 40 | V |
| Collector Output Voltage | VC1, VC2 | - | - | 42 | V |
| Collector Output Current (Each transistor) | IC1, IC2 | - | - | 500 mA | mA |
| Operating Junction Temperature | TJ | - | - | 125 | °C |
| Storage Temperature Range | Tstg | -55 | - | 125 | °C |
| Operating Ambient Temperature Range | TA | -40 | - | 125 | °C |
| Reference Voltage (IO = 1.0 mA) | Vref | 4.75 | 5.0 | 5.25 | V |
| Oscillator Frequency (CT = 0.01 μF, RT = 12 kΩ) | fosc | 1.0 | 40 | 200 | kHz |
Key Features
- Complete PWM Power-Control Circuitry: Includes all necessary functions for constructing a PWM control circuit on a single chip.
- On-Chip Oscillator with Master or Slave Operation: Allows for flexible operation in various power supply configurations.
- On-Chip Error Amplifiers: Provides high accuracy and stability in feedback control.
- On-Chip 5.0 V Reference: Capable of sourcing up to 10 mA of load current with a 5% tolerance.
- Adjustable Deadtime Control: Enables control over the total range of dead time.
- Uncommitted Output Transistors: Rated to 500 mA source or sink current, suitable for push-pull or single-ended operation.
- Undervoltage Lockout: Protects the device from operating below the minimum voltage threshold.
- Pb-Free Packages Available: Compliant with environmental regulations.
Applications
- Desktop PCs: Used in power supply units for desktop computers.
- Microwave Ovens: Controls the power supply in microwave oven applications.
- Power Supplies: AC/DC, isolated, with or without Power Factor Correction (PFC).
- Server PSUs: Utilized in server power supply units.
- Solar Micro-Inverters: Employed in solar power inverter systems.
- Washing Machines: Used in both low-end and high-end washing machine power supplies.
- E-Bikes: Controls power supplies in electric bicycles.
- Telecom/Server AC/DC Supplies: Dual controller for analog power supplies.
- Smoke Detectors: Used in smoke detector power supply circuits.
- Solar Power Inverters: Employed in solar power inverter systems.
Q & A
- What is the primary function of the TL494BD?
The TL494BD is a fixed-frequency pulse-width-modulation (PWM) control circuit designed primarily for switch mode power supply control.
- What is the operating voltage range of the TL494BD?
The power supply voltage (VCC) range is from 7.0 V to 40 V.
- What is the maximum collector output current of the TL494BD?
The maximum collector output current (IC1, IC2) is 500 mA.
- What is the reference voltage provided by the TL494BD?
The TL494BD provides a stable 5.0 V reference voltage with a 5% tolerance.
- Can the TL494BD operate in push-pull or single-ended mode?
Yes, the TL494BD can operate in either push-pull or single-ended mode.
- What is the purpose of the undervoltage lockout feature in the TL494BD?
The undervoltage lockout feature protects the device from operating below the minimum voltage threshold.
- What are some common applications of the TL494BD?
Common applications include desktop PCs, microwave ovens, power supplies, server PSUs, solar micro-inverters, and more.
- What is the maximum operating junction temperature of the TL494BD?
The maximum operating junction temperature (TJ) is 125°C.
- Is the TL494BD available in Pb-free packages?
Yes, the TL494BD is available in Pb-free packages.
- How can the oscillator frequency of the TL494BD be adjusted?
The oscillator frequency can be adjusted using the timing resistor (RT) and timing capacitor (CT).
