Overview
The UCD7138DRSR is a high-performance, single-channel synchronous-rectifier driver produced by Texas Instruments. This device is designed for high-power, high-efficiency isolated converter applications, particularly where advanced synchronous-rectification (SR) control is required. It works in conjunction with the UCD3138A digital power controller to optimize dead-time settings and maximize system efficiency. The UCD7138DRSR features a low-side gate driver with body-diode conduction sensing and reporting, which is crucial for minimizing body-diode conduction time and enhancing system robustness.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Peak Source Current | 4 A | A |
| Peak Sink Current | 6 A | A |
| Supply Voltage Range | 4.5 to 18 V | V |
| Operating Frequency | Up to 2 MHz | Hz |
| Propagation Delay | 14 ns (typical) | ns |
| Rise and Fall Times | 5 ns (typical) | ns |
| Body-Diode Conduction Sensing Threshold | -150 mV | mV |
| Package Type | 6-pin WSON-6 (3 mm x 3 mm) | - |
| Undervoltage Lockout (UVLO) | Typically 3.8 V with 240 mV hysteresis | V |
Key Features
- Low-Side Gate Driver with Body-Diode Conduction Sensing and Reporting: Detects body-diode conduction time as low as 10 ns and reports this information to the UCD3138A digital power controller.
- Gate Turnon and Turnoff Edge Optimization: Optimizes dead-time settings for efficient operation, especially in synchronous rectification applications.
- Negative Current Protection: Provides robust protection against negative current conditions.
- Fast Propagation Delays and Rise/Fall Times: Ensures efficient operation at high frequencies with typical propagation delays of 14 ns and rise/fall times of 5 ns.
- Rail-to-Rail Drive Capability: Offers asymmetrical rail-to-rail drive capability with 4-A source and 6-A sink peak-current drive.
- Undervoltage Lockout (UVLO): Features internal UVLO protection to ensure the device operates within safe voltage ranges.
Applications
- LLC Converters: Particularly useful in half-bridge LLC converters where it helps in achieving high efficiency by closely approximating the behavior of an ideal diode.
- Hard Switching Full-Bridge Converters: Suitable for applications requiring high-power and high-efficiency synchronous rectification.
- Digital Power-Control Applications: Works seamlessly with the UCD3138A digital power controller to provide advanced SR control solutions.
Q & A
- What is the primary function of the UCD7138DRSR?
The UCD7138DRSR is a single-channel synchronous-rectifier driver designed to optimize dead-time settings and enhance system efficiency in high-power isolated converter applications.
- How does the UCD7138DRSR sense body-diode conduction?
The device uses an internal high-speed comparator with a -150 mV threshold to detect body-diode conduction and reports this information to the UCD3138A digital power controller.
- What is the peak current drive capability of the UCD7138DRSR?
The device has a peak source current of 4 A and a peak sink current of 6 A.
- What is the operating frequency range of the UCD7138DRSR?
The device can operate up to 2 MHz.
- What type of package does the UCD7138DRSR come in?
The device is available in a 6-pin WSON-6 package with dimensions of 3 mm x 3 mm.
- What is the purpose of the undervoltage lockout (UVLO) feature in the UCD7138DRSR?
The UVLO feature ensures that the device operates within safe voltage ranges, typically 3.8 V with a 240 mV hysteresis, to prevent malfunction or damage.
- In which types of converters is the UCD7138DRSR commonly used?
The device is commonly used in LLC converters, hard switching full-bridge converters, and other digital power-control applications.
- How does the UCD7138DRSR optimize gate turnon and turnoff edges?
The device optimizes gate turnon and turnoff edges by analyzing body-diode conduction information and adjusting dead-time settings accordingly, in conjunction with the UCD3138A digital power controller.
- What is the significance of the fast propagation delays and rise/fall times in the UCD7138DRSR?
The fast propagation delays (14 ns typical) and rise/fall times (5 ns typical) ensure efficient operation at high frequencies.
- How does the UCD7138DRSR enhance system robustness?
The device enhances system robustness through internal logic that guarantees the gate driver output is only high if the input signal is also high, and by providing negative current protection.
