Overview
The TL494CNSR, produced by Texas Instruments, is a highly integrated pulse-width-modulation (PWM) control circuit designed primarily for power-supply control. This device incorporates all the necessary functions for constructing a PWM control circuit on a single chip, offering flexibility to tailor the power-supply control circuitry to specific applications. It 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, 5%-precision regulator. The TL494CNSR is suitable for a wide range of power supply configurations, including AC/DC, isolated, and non-isolated supplies.
Key Specifications
| Parameter | Description | Value |
|---|---|---|
| Power Supply Voltage (VCC) | Maximum voltage that can be applied to the VCC pin | 42 V |
| Collector Output Voltage (VC1, VC2) | Maximum voltage that can be applied to the collector pins | 42 V |
| Operating Temperature Range | Temperature range for normal operation | 0°C to 70°C (TL494), –40°C to 85°C (TL494I) |
| Oscillator Frequency | Frequency of the on-chip oscillator | Approximately 40 kHz (with CT = 0.001 μF, RT = 30 kΩ) |
| Output Current Capability | Maximum current that the output transistors can sink or source | 200 mA |
| Reference Voltage | Output voltage of the internal 5-V reference regulator | 5 V with ±5% tolerance |
| Package Types | Available package types | SOIC (16), PDIP (16), SOP (16), TSSOP (16) |
Key Features
- Complete PWM Power-Control Circuitry: Includes all necessary components for PWM control on a single chip.
- On-Chip Adjustable Oscillator: Allows for master or slave operation and can be bypassed if needed.
- On-Chip Error Amplifiers: Two error amplifiers with a common-mode voltage range from –0.3 V to VCC – 2 V.
- Dead-Time Control Comparator: Provides approximately 5% dead time.
- Pulse-Steering Control Flip-Flop: Alternately directs the modulated pulse to each of the two output transistors.
- Uncommitted Output Transistors: Rated for 200 mA sink or source current, with common-emitter or emitter-follower output capability.
- Output Control: Selects single-ended or push-pull operation, with internal circuitry preventing double pulses at either output.
- Internal 5-V Reference Regulator: Provides a stable 5-V reference supply with ±5% tolerance.
- Variable Dead Time: Allows control over the total range of dead time.
- Undervoltage Lockout: Protects the device from operating below a certain voltage threshold.
Applications
- Desktop PCs: Power supplies for desktop computers.
- Server PSUs: Power supplies for server systems.
- Solar Micro-Inverters: Inverters used in solar power systems.
- Washing Machines: Power supplies for low-end and high-end washing machines.
- E-Bikes: Power supplies for electric bicycles.
- Telecom/Server AC/DC Supplies: Dual controller power supplies for telecom and server applications.
- Smoke Detectors: Power supplies for smoke detection systems.
- Microwave Ovens: Power supplies for microwave ovens.
Q & A
- What is the primary application of the TL494CNSR?
The TL494CNSR is primarily designed for power-supply control, including AC/DC, isolated, and non-isolated power supplies.
- What are the key components of the TL494CNSR?
The TL494CNSR 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 operating temperature range of the TL494CNSR?
The TL494CNSR operates from 0°C to 70°C, while the TL494I version operates from –40°C to 85°C.
- How is the oscillator frequency set in the TL494CNSR?
The oscillator frequency is set using external timing components RT and CT.
- What is the maximum output current capability of the TL494CNSR?
The output transistors can sink or source up to 200 mA of current.
- Can the TL494CNSR be used in push-pull or single-ended output configurations?
Yes, the TL494CNSR can be configured for either push-pull or single-ended output operation through the output-control function.
- What is the purpose of the dead-time control comparator in the TL494CNSR?
The dead-time control comparator provides approximately 5% dead time to prevent simultaneous conduction of the output transistors.
- Does the TL494CNSR have built-in undervoltage protection?
Yes, the TL494CNSR includes an undervoltage lockout feature to protect the device from operating below a certain voltage threshold.
- What are some common applications of the TL494CNSR?
Common applications include desktop PCs, server PSUs, solar micro-inverters, washing machines, e-bikes, and telecom/server AC/DC supplies.
- Is the TL494CNSR available in different package types?
Yes, the TL494CNSR is available in SOIC, PDIP, SOP, and TSSOP packages.
