NCP1050, NCP1051, NCP1052, NCP1053, NCP1054, NCP1055 - Monolithic High Voltage Gated Oscillator Power Switching Regulator

Oct 12, 2026

NCP1050 through NCP1055 are monolithic high voltage regulator ICs built for equipment that must meet low standby power requirements. They use rectified AC line operation and, in flyback converter systems, cover output power from 6.0 W to 40 W at fixed 100/115/230 V and 3.0 W to 20 W across 85–265 V with a variable input. An active startup regulator removes the need for a transformer auxiliary bias winding and supports overload protection timing, fast gated oscillator control, and protection features including undervoltage lockout, thermal shutdown, and auto-restart fault detection.

LanguageEnglish

CategoryTechnology

FormatPDF

Pages25

Reading Time1 h 3 min

AccessFree to download

Features

Typical Applications

Marking Diagrams

Ordering Information

Pin Function Description

Representative Block Diagram

Timing Diagram

NCP1050, NCP1051, NCP1052, NCP1053, NCP1054, NCP1055 Monolithic High Voltage Gated Oscillator Power Switching Regulator The NCP1050 through NCP1055 are monolithic high voltage regulators that enable end product equipment to be compliant with low standby power requirements. This device series combines the required converter functions allowing a simple and economical power system solution for office automation, consumer, and industrial products. These devices are designed to operate directly from a rectified AC line source. In flyback converter applications they are capable of providing an output power that ranges from 6.0 W to 40 W with a fixed AC input of 100 V, 115 V, or 230 V, and 3.0 W to 20 W with a variable AC input that ranges from 85 V to 265 V. This device series features an active startup regulator circuit that eliminates the need for an auxiliary bias winding on the converter transformer, fault detector and a programmable timer for converter overload protection, unique gated oscillator configuration for extremely fast loop response with double pulse suppression, power switch current limiting, input undervoltage lockout with hysteresis, thermal shutdown, and auto restart fault detection. These devices are available in economical 8−pin dual−in−line and 4−pin SOT−223 packages. Features • Startup Circuit Eliminates the Need for Transformer Auxiliary Bias Winding • Optional Auxiliary Bias Winding Override for Lowest Standby Power Applications • Converter Output Overload and Open Loop Protection • Auto Restart Fault Protection • IC Thermal Fault Protection • Unique, Dual Edge, Gated Oscillator Configuration for Extremely Fast Loop Response • Oscillator Frequency Dithering with Controlled Slew Rate Driver for Reduced EMI • Low Power Consumption Allowing European Blue Angel Compliance • On−Chip 700 V Power Switch Circuit and Active Startup Circuit • Rectified AC Line Source Operation from 85 V to 265 V • Input Undervoltage Lockout with Hysteresis • Oscillator Frequency Options of 44 kHz, 100 kHz, 136 kHz • These are Pb−Free and Halide−Free Devices Typical Applications • AC−DC Converters • Wall Adapters • Portable Electronic Chargers • Low Power Standby and Keep−Alive Supplies [http://onsemi.com](http://onsemi.com) MARKING DIAGRAMS 8 1 Pin: 1 . 2. PDIP −8 P SUFFIX CASE 626A V CC Control Input 3, 7−8 . Ground 4. No Connection 5. Power Switch Drain SOT −223 ST SUFFIX CASE 318E 1 Pin: 1.V CC 2. Control Input 3. Power Switch Drain 4. Ground AYW N5XZ􀀂􀀂 X = Current Limit (0, 1, 2, 3, 4, 5) Z = Oscillator Frequency A = 44 kHz, B = 100 kHz, C = 136 kHz A = Assembly Location WL, = Wafer Lot YY, Y = Year WW, W = Work Week G or 􀀂 = Pb−Free Package (Note: Microdot may be in either location) ORDERING INFORMATION See detailed ordering and shipping information on page 22 of this data sheet. NCP1050, NCP1051, NCP1052, NCP1053, NCP1054, NCP1055 3, 7−8 Control Snubber Figure 1. Typical Application Pin Function Description | Pin
(SOT −223) | Pin
(PDIP −8) | Function | Description | | --- | --- | --- | --- | | 1 | 1 | V CC | This is the positive supply voltage input. During startup, power is supplied to this input from Pin 5. When V CC reaches V CC(on), the Startup Circuit turns off and the output is allowed to begin switching with 1.0 V hysteresis on the V CC pin. The capacitance connected to this pin programs fault timing and frequency modulation rate. | | 2 | 2 | Control Input | The Power Switch Circuit is turned off when a current greater than approximately 50 􀀂Ais drawn out of or applied to this pin. A 10 V clamp is built onto the chip to protect the device from ESD damage or overvoltage conditions. | | 4 | 3, 7, 8 | Ground | This pin is the control circuit and Power Switch Circuit ground. It is part of the integrated circuit lead frame. | | − | 4 | No Connection | | | 3 | 5 | Power Switch
Drain | This pin is de

FAQs

What problem do the NCP1050–NCP1055 regulators address?

They provide high-voltage monolithic regulation that helps end equipment comply with low standby power requirements, including flyback converter use cases.

How do these devices start up without a transformer auxiliary bias winding?

They include an active startup regulator circuit that eliminates the need for an auxiliary bias winding on the converter transformer.

Which protection and control functions are featured in the NCP1050–NCP1055 series?

They provide overload and open-loop protection with a programmable timer, auto-restart fault protection, IC thermal shutdown, input undervoltage lockout with hysteresis, and gated-oscillator configuration with double pulse suppression and frequency dithering for reduced EMI.

Oct 12, 2026

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