Overview
The TL494ING4, produced by Texas Instruments, is a pulse-width-modulation (PWM) control circuit integrated into a single chip. It is designed primarily for power-supply control and offers the flexibility to tailor the power-supply control circuitry to specific applications. The device includes two error amplifiers, an on-chip adjustable oscillator, a dead-time control (DTC) comparator, a pulse-steering control flip-flop, and a 5-V reference regulator. This architecture allows for easy synchronization and prohibits double pulsing at either output, ensuring reliable operation in various power supply configurations.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| VCC Supply Voltage | - | - | 41 | V |
| VI Amplifier Input Voltage | - | - | VCC + 0.3 | V |
| VO Collector Output Voltage | - | - | 41 | V |
| IO Collector Output Current | - | - | 250 | mA |
| Lead Temperature (1/16 inch from case for 10 seconds) | - | - | 260 | °C |
| Tstg Storage Temperature Range | -65 | - | 150 | °C |
| Input Offset Voltage (Error Amplifier) | 2 | 10 | - | mV |
| Open-Loop Voltage Amplification (Error Amplifier) | 70 | 95 | - | dB |
| Unity-Gain Bandwidth (Error Amplifier) | - | 800 | - | kHz |
| Rise Time (Common-Emitter Configuration) | 100 | 200 | - | ns |
| Fall Time (Common-Emitter Configuration) | 25 | 100 | - | ns |
Key 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 Pulse at Either Output
- Variable Dead Time Provides Control Over Total Range
- Internal Regulator Provides a Stable 5-V Reference Supply With 5% Tolerance
- Circuit Architecture Allows Easy Synchronization
- Two High-Gain Error Amplifiers with Common-Mode Input Voltage Range from –0.3 V to VCC – 2 V
- On-Chip Adjustable Oscillator with Programmable Frequency
- Pulse-Steering Control Flip-Flop and Dead-Time Control Comparator
- Output Transistors Configured as Open Collector/Open Emitter, Capable of Sinking or Sourcing Up to 200 mA
Applications
- Desktop PCs
- Microwave Ovens
- Power Supplies: AC/DC, Isolated, With or Without PFC
- Server PSUs
- Solar Micro-Inverters
- Washing Machines: Low-End and High-End
- E-Bikes
- Telecom/Server AC/DC Supplies: Dual Controller: Analog
- Smoke Detectors
- Solar Power Inverters
Q & A
- What is the primary function of the TL494?
The TL494 is a pulse-width-modulation (PWM) control circuit designed primarily for power-supply control.
- What are the key components of the TL494?
The TL494 includes two error amplifiers, an on-chip adjustable oscillator, a dead-time control comparator, a pulse-steering control flip-flop, and a 5-V reference regulator.
- What is the range of the supply voltage for the TL494?
The supply voltage (VCC) for the TL494 ranges from 7 V to 40 V.
- How is the oscillator frequency programmed in the TL494?
The oscillator frequency is programmed by selecting the timing components RT and CT. The frequency is determined by the external timing resistor (RT) and capacitor (CT).
- What is the purpose of the 5-V reference regulator in the TL494?
The 5-V reference regulator provides a stable reference voltage and acts as a preregulator, establishing a stable supply for the device's internal circuits.
- Can the TL494 operate in both single-ended and push-pull configurations?
Yes, the TL494 can operate in both single-ended and push-pull configurations, selectable through the output-control function.
- What is the maximum output current of the TL494's output transistors?
The output transistors of the TL494 are capable of sinking or sourcing up to 200 mA.
- What are some common applications of the TL494?
The TL494 is used in various applications including desktop PCs, microwave ovens, power supplies, server PSUs, solar micro-inverters, and more.
- How does the TL494 prevent double pulsing at either output?
The TL494's internal circuitry prohibits double pulsing at either output, ensuring reliable operation in push-pull configurations.
- What is the operating temperature range for the TL494?
The TL494 is characterized for operation from 0°C to 70°C, while the TL494I is characterized for operation from –40°C to 85°C.
- How does the error amplifier in the TL494 function?
The error amplifiers in the TL494 receive their bias from the VI supply rail and have a common-mode input voltage range from –0.3 V to VCC – 2 V. They behave characteristically of a single-ended single-supply amplifier.
