NCP1253 Series

PWM Controller, Current Mode, for Offline Power Supplies

Catalog

PWM Controller, Current Mode, for Offline Power Supplies

Part	Mounting Type	Output Isolation	Voltage - Supply (Vcc/Vdd) [Max]	Voltage - Supply (Vcc/Vdd) [Min]	Supplier Device Package	Voltage - Start Up	Duty Cycle	Operating Temperature [Min]	Operating Temperature [Max]	Fault Protection	Package / Case	Frequency - Switching	Topology	Control Features	Operating Temperature
ON Semiconductor NCP1253BSN100T1G	Surface Mount	Isolated	28 V	8.8 V	6-TSOP	18 V	80 %	-40 °C	125 ¯C	Over Voltage Short Circuit	SOT-23-6 Thin TSOT-23-6	100 kHz	Flyback
ON Semiconductor NCP1253ASN65T1G	Surface Mount	Isolated	28 V	8.8 V	6-TSOP	18 V	80 %	-40 °C	125 ¯C	Over Voltage Short Circuit	SOT-23-6 Thin TSOT-23-6	65 kHz	Flyback
ON Semiconductor NCP1253ASN100T1G	Surface Mount	Isolated	28 V	8.8 V	6-TSOP	18 V	80 %	-40 °C	125 ¯C	Over Voltage Short Circuit	SOT-23-6 Thin TSOT-23-6	100 kHz	Flyback
ON Semiconductor NCP1253BSN65T1G	Surface Mount	Isolated	28 V	8.8 V	6-TSOP	18 V	80 %			Current Limiting Open Loop Over Voltage Short Circuit	SOT-23-6 Thin TSOT-23-6	65 kHz	Flyback	Frequency Control Soft Start	150 °C

Catalog

PWM Controller, Current Mode, for Offline Power Supplies

Key Features

• Frequency Foldback down to 26 kHz and Skip-Cycle in Light Load

• Internal Ramp Compensation

• Frequency Jittering in Normal and Frequency Foldback modes

• Over Voltage Protection (OVP) monitoring on the Vcc pin

• Timer-based Auto-Recovery or Latched Short-Circuit Protection

Description

The NCP1253 is a highly integrated PWM controller capable of delivering a rugged and high performance offline power supply in a tiny TSOP-6 package. With a supply range up to 28 V, the controller hosts a jittered 65 kHz 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 it's switching frequency down to a minimum level of 26 kHz. As the power further goes down, the part enters skip cycle while limiting the peak current. To avoid sub harmonic oscillations in CCM operation, adjustable slope compensation is available via the series inclusion of a simple resistor in the current sense signal. Besides the auto-recovery timer-based short-circuit protection, an Over Voltage Protection on the Vcc pin protects the whole circuitry in case of optocoupler destruction or adverse open loop operation.