NCP1239 Series

Fixed Frequency Current Mode Controller for Flyback Converter with HV startup

Catalog

Fixed Frequency Current Mode Controller for Flyback Converter with HV startup

Part	Supplier Device Package	Voltage - Start Up	Operating Temperature [Min]	Operating Temperature [Max]	Duty Cycle	Output Isolation	Mounting Type	Fault Protection	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Package / Case [custom]	Package / Case	Package / Case [custom]	Package / Case	Topology	Frequency - Switching	Control Features	Operating Temperature	Package / Case [x]	Package / Case [y]
ON Semiconductor NCP1239BD100R2G	7-SOIC	12 V	-40 °C	125 ¯C	80 %	Isolated	Surface Mount	Current Limiting Over Load Over Temperature Over Voltage	35 V	8.8 V	7	8-SOIC	3.9 mm	0.154 in	Flyback	100 kHz
ON Semiconductor NCP1239AD65R2G	7-SOIC	12 V	-40 °C	125 ¯C	80 %	Isolated	Surface Mount	Current Limiting Over Load Over Temperature Over Voltage	35 V	8.8 V	7	8-SOIC	3.9 mm	0.154 in	Flyback	65 kHz
ON Semiconductor NCP1239ND65R2G	7-SOIC	12 V	-40 °C	125 ¯C	80 %	Isolated	Surface Mount	Current Limiting Over Load Over Temperature Over Voltage	35 V	8.8 V	7	8-SOIC	3.9 mm	0.154 in	Flyback	65 kHz
ON Semiconductor NCP1239DD100R2G	7-SOIC	12 V			80 %	Isolated	Surface Mount	Current Limiting Over Load Over Power Over Temperature Over Voltage Short Circuit	35 V	8.8 V	7	8-SOIC	3.9 mm	0.154 in	Flyback	100 kHz	Soft Start	150 °C
ON Semiconductor NCP1239VDR2	16-SOIC	16.4 V	0 °C	150 °C	80 %	Isolated	Surface Mount	Current Limiting Over Load	36 V	11.2 V		16-SOIC			Forward	250 kHz	Frequency Control Sync		0.154 in	3.9 mm
ON Semiconductor NCP1239LD100R2G	7-SOIC	12 V			80 %	Isolated	Surface Mount	Current Limiting Over Load Over Power Over Temperature Over Voltage Short Circuit	35 V	8.8 V	7	8-SOIC	3.9 mm	0.154 in	Flyback Secondary Side SR	100 kHz	EN Frequency Control Soft Start	150 °C

Catalog

Fixed Frequency Current Mode Controller for Flyback Converter with HV startup

Key Features

• Fixed-frequency 65-kHz or 100-kHz current-mode control operation

• Frequency foldback down to 26 kHz and skip mode

• Adjustable Over Power Protection (OPP) circuit

• High-voltage Current Source with Brown-out (BO) detection

• Internal ramp compensation

• Internal fixed 8-ms soft-start

• Frequency jittering in normal and frequency foldback modes

• 64-ms timer-based short-circuit protection with auto-recovery or latched operation

• Pre-short ready

• Latched OVP on Vcc (NCP1239 A & B versions)

• Latched OVP/OTP input for improved robustness

• 35-V Vcc operation

• +500 mA/ -500 mA peak source/sink drive capability

• Internal thermal shutdown

• Extremely low no-load standby power

• Pin-to-pin compatible with the existing NCP1236/1247 series

Description

The NCP1239 is a fixed-frequency current-mode controller featuring the Dynamic Self-Supply. This function greatly simplifies the design of the auxiliary supply and the Vcc capacitor by activating the internal startup current source to supply the controller during start-up, transients, latch, stand-by etc. With a supply range up to 35 V, the controller hosts a jittered 65 or 100-kHz switching circuitry operated in peak current mode control. When the power on the secondary side starts to decrease, the controller automatically folds back its switching frequency down to minimum level of 26 kHz. As the power further goes down, the part enters skip cycle while limiting the peak current that insures excellent efficiency in light load condition. It features a timer-based fault detection that ensures the detection of overload and an adjustable compensation to help keep the maximum power independent of the input voltage.