Overview
The UCC28740-Q1 is an ultra-low standby, flyback controller designed by Texas Instruments for automotive applications. This device is AEC-Q100 qualified, ensuring it meets stringent automotive standards with a temperature grade 1 rating of -40°C to +125°C. It features an internal 700-V startup switch, dynamically controlled operating states, and a tailored modulation profile to achieve ultra-low standby power without compromising startup time or output transient response. The controller uses an optical coupler for feedback, providing fast transient response to large-load steps and operates in discontinuous conduction mode (DCM) with valley-switching to minimize switching losses.
Key Specifications
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Device Temperature Grade | -40 | +125 | °C | |
| HBM Classification Level | ±2 | kV | ||
| CDM Classification Level | ±750 | V | ||
| No-Load Power Capability | <10 | mW | ||
| Voltage Regulation Accuracy | ±1% | |||
| Current Regulation Accuracy | ±5% | |||
| Startup Switch Voltage | 700 | V | ||
| Maximum Switching Frequency | 100 | kHz | ||
| Minimum Switching Frequency | 170 | Hz | ||
| Package Type | SOIC-7 | |||
| Body Size (Nominal) | 4.90 mm × 3.91 mm |
Key Features
- Qualified for automotive applications with AEC-Q100 qualification.
- Functional Safety-Capable with documentation available to aid functional safety system design.
- Less than 10-mW no-load power capability.
- Enables ±1% voltage regulation and ±5% current regulation across line and load.
- Internal 700-V startup switch.
- Maximum switching frequency of 100 kHz for high-power-density charger designs.
- Resonant-ring valley-switching operation for highest overall efficiency.
- Frequency dithering to ease EMI compliance.
- Clamped gate-drive output for MOSFET.
- Overvoltage, low-line, and overcurrent protection functions.
- Support for custom design using the WEBENCH Power Designer.
Applications
- Ultra-low standby power flyback with integrated HV startup and optocoupler feedback.
- Traction inverter HV to LV backup supply.
- HVAC compressor HV isolated power supply.
- PTC heater HV isolated power supply.
Q & A
- What is the temperature range for the UCC28740-Q1?
The device operates within a temperature range of -40°C to +125°C.
- What is the maximum switching frequency of the UCC28740-Q1?
The maximum switching frequency is 100 kHz.
- What type of switching mode does the UCC28740-Q1 operate in?
The controller operates in discontinuous conduction mode (DCM) with valley-switching.
- What is the no-load power capability of the UCC28740-Q1?
The device has a no-load power capability of less than 10 mW.
- Does the UCC28740-Q1 have built-in protection features?
Yes, it includes overvoltage, low-line, and overcurrent protection functions.
- How does the UCC28740-Q1 achieve high efficiency?
The device uses resonant-ring valley-switching operation and modulation of switching frequency and primary current-peak amplitude to achieve high efficiency.
- What is the purpose of the internal 700-V startup switch?
The internal 700-V startup switch provides fast charging of the VDD capacitor during startup.
- Is the UCC28740-Q1 suitable for automotive applications?
Yes, it is qualified for automotive applications and meets AEC-Q100 standards.
- Can the UCC28740-Q1 be used for functional safety applications?
Yes, it is Functional Safety-Capable with available documentation to aid in functional safety system design.
- How can I design a custom power supply using the UCC28740-Q1?
You can create a custom design using the UCC28740-Q1 with the WEBENCH Power Designer.
