Calculation tool
UCC25661X-CALC — UCC25661X Design Calculator
The purpose of this tool is to aid in the design of the main power stage components of a LLC Resonant Converter along with component calculations using UCC25661x controller.
Data sheet
UCC25661-Q1
- Full-load switching frequency: 50kHz to 750kHz
- IPPC control enables wide input and output LLC (WLLC) operation
- Enhanced light load management:
- High-frequency pulse skip for improved light load efficiency
- Low-frequency burst for low standby power
- Audible frequency range skip for reduced audible noise
- Integrated PFC on/off control signal to help further reduce standby power (UCC256614-Q1)
- Internal resonant-capacitor voltage synthesizer for enhanced signal reliability and high start-up frequency support
- Zero current switching (ZCS) avoidance to eliminate capacitive region operation
- Adaptive soft start with minimized inrush current
- Integrated high-voltage start-up (UCC256612-Q1 and UCC256614-Q1)
- Integrated gate driver: +0.6A and –1.2A
- Complete protections
- Overcurrent protection (OCP): 50ns, cycle-by-cycle current limit
- Overvoltage protection (OVP), internal and external overtemperature protection (OTP)
- Input and VCCP UVLO with internal 19V VCCP Clamp
- Independently configured OCP and overload protection (OLP) (UCC256612-Q1, UCC256613-Q1, and UCC256614-Q1)
- SOIC-14 package with removed pins for high-voltage clearance
The UCC25661x-Q1 family is a high-frequency LLC controller that implements a input-power proportional control (IPPC) scheme, along with enhanced light-load management and multiple protection features.
IPPC widens the control range of the LLC converter and simplifies the design of wide input applications, such as high voltage to low voltage (HV-LV) redundant auxiliary, key-off, and bias isolated power supplies. IPPC simplifies the design of wide output applications, such as light electric vehicle battery chargers (scooters, mopeds, golf carts, and fork lifts).
The UCC25661x-Q1 family has enhanced light-load management that improves efficiency and minimizes audible noise. To minimize standby power in charger applications, the UCC25661x-Q1 family directly disables the PFC controller when operating in burst mode.
The automatic capacitive region avoidance scheme, along with the adaptive soft start with a reverse recovery avoidance scheme, establishes that the device never works in a mode where there is a potential to damage the FETs. Because of the automatic capacitive region avoidance scheme, the controller works best with a prebiased load.
The UCC25661x-Q1 family comes with robust protection for designing a reliable power supply. The UCC25661x-Q1 family has options supporting various features, see details in the Device Comparison table.
Technical documentation
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View all 6 | Type | Title | Date | ||
|---|---|---|---|---|
| * | Data sheet | UCC25661x-Q1 Family 750kHz Wide VIN /VOUT Range LLC Controller Optimized for Light-Load Efficiency datasheet (Rev. A) | PDF | HTML | 04 Sep 2025 |
| Product overview | UCC25661(-Q1) Selection Guide | PDF | HTML | 04 Sep 2025 | |
| Functional safety information | UCC25661x-Q1 Functional Safety FIT Rate, FMD and Pin FMA | PDF | HTML | 29 Jul 2025 | |
| Technical article | LLC 토폴로지를 이용해 자동차 설계자가 전력 밀도와 안정성을 강화 하도록 지원 | PDF | HTML | 19 May 2025 | |
| Technical article | 幫助汽車設計師藉由 LLC 拓撲結構提升功率密度與系統可靠性 | PDF | HTML | 19 May 2025 | |
| Technical article | Enabling automotive designers to increase power-density and reliability with LLC topology | PDF | HTML | 02 May 2025 |
Design & development
For additional terms or required resources, click any title below to view the detail page where available.
Evaluation board
UCC25661EVM-128 — UCC25661 evaluation module
The UCC25661 evaluation module (EVM) assists designers to evaluate the operation and performance of the UCC25661x LLC Resonant controller (16-pin SOIC package with removed pins for high voltage clearance). This evaluation module demonstrates how UCC25661x controls the LLC resonant half bridge DC-DC (...)
Reference designs
PMP31342 — Automotive 300W µDC/DC converter reference design using half-bridge LLC
This automotive µDC/DC converter reference design demonstrates a non-synchronous half-bridge inductor inductor-capacitor (LLC) converter, which covers an input voltage range of 225V to 450V using the UCC256612-Q1. The output voltage is 48V with a maximum load current of 6.25A. The design can (...)
Test report: PDF
Reference designs
PMP23464 — Universal input, 500W constant current and constant voltage e-bike charger reference design
This reference design is a universal input, 71.4V, 7A constant current (CC), constant voltage (CV) charger for e-bike applications. The reference design achieves 92.93% end-to-end peak efficiency with a 115Vac input, and 94.50% end-to-end peak efficiency with a 230Vac input. This design includes (...)
Test report: PDF
Reference designs
PMP41106 — Universal input, 500W constant current and constant voltage E-bike charger reference design
This reference design is a universal input, 48V, 10.4A constant current (CC), constant voltage (CV) charger for e-bike applications. The reference design achieves 91.5% end-to-end peak efficiency with a 110Vac input, and 93.50% end-to-end peak efficiency with a 230Vac input. This design includes (...)
Test report: PDF
| Package | Pins | CAD symbols, footprints & 3D models |
|---|---|---|
| SOIC (DDB) | 14 | Ultra Librarian |
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