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UCC28750

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Current-mode flyback controller with secondary-side regulation (SSR) for offline applications

Product details

Operating temperature range (°C) -40 to 125 Control mode Current Topology Buck, Flyback Rating Catalog Features Brown Out, Burst mode, CCM, Current limiting, Cycle-by-cycle over-current protection, Cycle-by-cycle overcurrent protection, DCM, Fixed frequency, Frequency Dithering, Light load efficiency, Light-load efficiency, Output short-circuit protection, Over Temperature Protection, Over Voltage Protection, Overcurrent protection, SSR, Secondary-side regulated, Soft start, Under voltage lock out
Operating temperature range (°C) -40 to 125 Control mode Current Topology Buck, Flyback Rating Catalog Features Brown Out, Burst mode, CCM, Current limiting, Cycle-by-cycle over-current protection, Cycle-by-cycle overcurrent protection, DCM, Fixed frequency, Frequency Dithering, Light load efficiency, Light-load efficiency, Output short-circuit protection, Over Temperature Protection, Over Voltage Protection, Overcurrent protection, SSR, Secondary-side regulated, Soft start, Under voltage lock out
SOT-23 (DBV) 6 8.12 mm² 2.9 x 2.8
  • Stable continuous conduction mode (CCM) operation with internal slope compensation
  • Fixed-frequency operation of 65kHz or 100kHz
  • Secondary-side regulation (SSR) with opto-coupler
  • Frequency foldback and burst mode for improved light-load efficiency
  • Frequency dithering for improved EMI performance
  • Gate source/sink capability: 300mA/500mA
  • Internal 4ms soft-start
  • Robust protection features:
    • Over-voltage and Under-voltage lockout
    • Output over-power protection (OPP)
    • Output short-circuit (OSC) protection
    • Output over-voltage (OVP) protection
    • Cycle-by-cycle peak over-current limit
    • External over-temperature, over-voltage protection (OTP, OVP) and brownout detection on FLT pin
    • Internal thermal shutdown
  • Stable continuous conduction mode (CCM) operation with internal slope compensation
  • Fixed-frequency operation of 65kHz or 100kHz
  • Secondary-side regulation (SSR) with opto-coupler
  • Frequency foldback and burst mode for improved light-load efficiency
  • Frequency dithering for improved EMI performance
  • Gate source/sink capability: 300mA/500mA
  • Internal 4ms soft-start
  • Robust protection features:
    • Over-voltage and Under-voltage lockout
    • Output over-power protection (OPP)
    • Output short-circuit (OSC) protection
    • Output over-voltage (OVP) protection
    • Cycle-by-cycle peak over-current limit
    • External over-temperature, over-voltage protection (OTP, OVP) and brownout detection on FLT pin
    • Internal thermal shutdown

UCC28750 is a highly-integrated current-mode, continuous-conduction-capable, PWM controller optimized for high performance, low standby power, and cost effective offline flyback converter applications using an opto-coupler. During light-load conditions the device enters frequency foldback and burst modes, improving light-load efficiency. The burst-mode algorithm used in UCC28750 controls the minimum effective switching frequency to prevent audible noise during light-load conditions. Frequency dithering improves EMI performance, and is active in normal, frequency foldback, and power boost operations.

UCC28750 provides protection features that enable a robust converter design with minimal external components. Output over-power protection (OPP) and cycle-by-cycle over-current limit protect the load and power-stage components from electrical stress. Over-voltage and under-voltage lockout (OVLO and UVLO) prevent switching in unwanted input conditions. The FLT pin provides line brown-out sensing and protection, or external over-temperature and over-voltage protection, depending on the device variant. The FLT pin is also used to disable the device through external control by pulling the pin to ground, regardless of the device variant.

UCC28750 is a highly-integrated current-mode, continuous-conduction-capable, PWM controller optimized for high performance, low standby power, and cost effective offline flyback converter applications using an opto-coupler. During light-load conditions the device enters frequency foldback and burst modes, improving light-load efficiency. The burst-mode algorithm used in UCC28750 controls the minimum effective switching frequency to prevent audible noise during light-load conditions. Frequency dithering improves EMI performance, and is active in normal, frequency foldback, and power boost operations.

UCC28750 provides protection features that enable a robust converter design with minimal external components. Output over-power protection (OPP) and cycle-by-cycle over-current limit protect the load and power-stage components from electrical stress. Over-voltage and under-voltage lockout (OVLO and UVLO) prevent switching in unwanted input conditions. The FLT pin provides line brown-out sensing and protection, or external over-temperature and over-voltage protection, depending on the device variant. The FLT pin is also used to disable the device through external control by pulling the pin to ground, regardless of the device variant.

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Technical documentation

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Type Title Date
* Data sheet UCC28750 Current-Mode Flyback Controller with Secondary-Side Regulation (SSR) for Off-Line Applications datasheet PDF | HTML 01 Apr 2022
Technical article 輔助返馳電源供應的注意事項 (Rev. A) PDF | HTML 09 Sep 2024
Technical article 보조 플라이백 전원 공급 장치에 대한 고려 사항 (Rev. A) PDF | HTML 09 Sep 2024
Technical article Considerations for auxiliary flyback power supplies (Rev. A) PDF | HTML 06 Sep 2024
Application note Retrofit UCC28750 EVM to Support Aux Power Application PDF | HTML 06 Jun 2024
Technical article 단일 커패시터를 추가하여 듀얼 출력 플라이백 전원 공급 장치의 교차 조정 개선 PDF | HTML 22 Mar 2024
Technical article 플라이백 컨버터 스너빙 PDF | HTML 22 Mar 2024
Technical article 新增單一電容器以增進雙輸出返馳電源供應器的交互穩壓 PDF | HTML 20 Mar 2024
Technical article 緩衝返馳式轉換器 PDF | HTML 20 Mar 2024
Technical article Snubbing the flyback converter PDF | HTML 26 Feb 2024
Technical article Adding a single capacitor to improve cross-regulation in dual-output flyback power supplies PDF | HTML 21 Dec 2023
Certificate UCC28750EVM-071 EU Declaration of Conformity (DoC) 20 Nov 2023
EVM User's guide Using the UCC28750EVM-071 60-W AC to DC Converter Evaluation Module User's Guide PDF | HTML 15 Nov 2023

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Evaluation board

UCC28750EVM-071 — UCC28750 evaluation module for current-mode flyback controller

The UCC28750EVM-071 is a 60-W evaluation module for evaluating an off-line AC to DC power converter. The UCC28750EVM-071 is intended for evaluation purposes and is not intended to be an end product. The UCC28750EVM-071 converts 85-VRMS to 265-VRMS input voltage down to 24 VDC, capable of delivering (...)
User guide: PDF | HTML
Not available on TI.com
Calculation tool

UCC28750-CALC Excel calculator tool for the UCC28750 Flyback controller

The UCC28750 Excel calculator helps build the schematic design and accelerate the design process.
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
UCC28750 Current-mode flyback controller with secondary-side regulation (SSR) for offline applications
Simulation tool

UCC28750-SIMPLIS UCC28750 Flyback Controller SIMPLIS Model

The UCC28750 SIMPLIS model helps build the schematic design and accelerates the design process.
Supported products & hardware

Supported products & hardware

Products
AC/DC & DC/DC controllers (external FET)
UCC28750 Current-mode flyback controller with secondary-side regulation (SSR) for offline applications
Reference designs

PMP31288 — 7.8W wide AC input non-isolated high-side buck reference design

The is an ultra wide input offline high-side buck power supply reference design that provides an 13V output at a maximum of 0.6A. The input accepts a voltage range of 85 VAC to 485 VAC. The reference design uses the UCC28750 current-mode flyback controller with opto-coupler feedback. The design is (...)
Test report: PDF
Package Pins CAD symbols, footprints & 3D models
SOT-23 (DBV) 6 Ultra Librarian

Ordering & quality

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