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ON NCP1239DD65R2G 65kHz Current Mode Controller For Flyback Converter With HV Startup

Shenzhen Mingjiada Electronics Co., Ltd., a globally renowned distributor of electronic components, now supplies ON's NCP1239DD65R2G fixed-frequency current-mode controller. This high-performance NCP1239DD65R2G controller is specifically designed for flyback converters with high-voltage start-up capability, operating at a switching frequency of 65kHz. It finds extensive application across various AC-DC conversion scenarios.

【NCP1239DD65R2G Product Overview】

The NCP1239DD65R2G is a fixed-frequency current-mode controller from ON, housed in a SOIC-7 package. This device incorporates dynamic self-powering capability, significantly simplifying auxiliary power supply and Vcc capacitor design.

This NCP1239DD65R2G controller integrates a high-voltage start-up circuit, supporting supply voltages up to 35V. Operating at a 65kHz switching frequency under peak current-mode control, it demonstrates exceptional light-load management capability. When power decreases, it automatically reduces the switching frequency to 26kHz and enters skip-cycle mode under further light loads.

Suitable for flyback topologies, the NCP1239DD65R2G delivers an isolated output with a maximum duty cycle of 80%, meeting diverse offline power supply design requirements.

【NCP1239DD65R2G Specifications】

Topology: Flyback

Output channels: 1

Switching frequency: 65kHz

Maximum duty cycle: 84%

Output voltage: 13.5V

Output current: 500mA

Minimum operating temperature: -40°C

Maximum operating temperature: +125°C

Mounting method: Surface mount (SMD/SMT)

Package type: SOIC-7

Description/function: Fixed-frequency current-mode controller

Fall time: 30 ns

Isolation type: Non-isolated

Operating supply current: 1.4 mA

Operating Supply Voltage:    8.8 V to 35 V

Product Category:    Current Mode Controller

Product Type:    Switching Controller

Rise Time:    40 ns

【Core Technical Features and Advantages of NCP1239DD65R2G】

The NCP1239DD65R2G is the preferred choice for numerous AC-DC power supply designs due to its meticulously engineered features:

Dynamic Self-Supply (DSS) with High-Voltage Start-up: The NCP1239DD65R2G controller incorporates an internal high-voltage start-up current source. This feature powers the controller's internal circuitry during start-up, transients, latch-up, and standby phases without requiring an external auxiliary power supply, simplifying design and reducing BOM costs. Its operating voltage range extends up to 35V, providing ample design margin.

Advanced Frequency Management: The NCP1239DD65R2G operates at a fixed 65kHz switching frequency. Upon detecting light loads, it automatically reduces the switching frequency to 26kHz and enters skip-cycle mode as power further decreases. This effectively minimises switching losses, achieving exceptionally high light-load and standby efficiency.

Comprehensive Protection Features: The NCP1239DD65R2G device integrates an adjustable overpower protection (OPP) circuit with high-voltage current source and brown-out (BO) detection capabilities. An internal fixed soft-start enhances system reliability. Its fault protection mechanisms include current limiting, overload, overtemperature, and overvoltage protection, ensuring safe system operation.

Overload Protection (OPP): Adjustable overpower protection circuit allowing designers to customise protection thresholds according to application requirements.

Overvoltage Protection (OVP) and Over-Temperature Protection (OTP): Offers selectable latch or auto-recovery modes.

Timer-based Short-Circuit Protection: Utilises a 64-millisecond timer to detect short-circuit faults, configurable for auto-recovery or latch operation to prevent chip damage under sustained fault conditions.

Undervoltage Lockout (UVLO): Ensures output shutdown during insufficient supply voltage to protect power switch transistors.

Additional Key Features of NCP1239DD65R2G:

Internal slope compensation: Stabilises peak current-mode control and prevents subharmonic oscillations.

Internal fixed soft-start (8ms): Reduces inrush current during startup.

Frequency jittering technology: Spreads switching frequency across a narrow bandwidth, significantly reducing conducted electromagnetic interference (EMI) and simplifying filter design.

Robust drive capability: Provides ±500 mA peak sink and source current capability, enabling direct driving of larger MOSFET switches.

Extremely low no-load standby power consumption: Aids compliance with stringent energy efficiency regulations.

The NCP1239DD65R2G supports frequency jittering functionality, effectively reducing EMI filter costs. The controller also provides 64-millisecond timer short-circuit protection with selectable automatic recovery or lockout operation, enhancing application flexibility.

【NCP1239DD65R2G Application Areas】

The NCP1239DD65R2G finds extensive use in diverse electronic equipment, including AC-DC converters for televisions, set-top boxes, and printers, as well as off-line adapters for notebook computers and netbooks.

This NCP1239DD65R2G controller is equally suited for industrial applications requiring efficient power management, such as industrial control systems, communication equipment, and embedded systems. Its high reliability and comprehensive protection features make it an ideal choice for high-performance power supply designs.

With advancements in new energy and IoT technologies, the NCP1239DD65R2G can also be deployed in new energy ICs and IoT ICs, meeting the stringent power management demands of modern electronic devices.