ON Semiconductor

The NCP1351 is a current mode controller targeting low power off line flyback Switched Mode Power Supplies (SMPS) where cost is of utmost importance. Based on a fixed peak current technique (quasi fixed TON), the controller decreases its switching frequency as the load becomes lighter. As a result, a power supply using the NCP1351 naturally offers excellent no load power consumption, while optimizing the efficiency in other loading conditions. When the frequency decreases, the peak current is gradually reduced down to approximately 30% of the maximum peak current to prevent transformer mechanical resonance. The risk of acoustic noise is thus greatly diminished while keeping good standby power performance.An externally adjustable timer permanently monitors the feedback activity and protects the supply in presence of a short circuit or an overload. Once the timer elapses, NCP1351 stops switching and stays latched for version A, and tries to restart for Version B.The internal structure features an optimized arrangement which allows one of the lowest available startup current, a fundamental parameter when designing low standby power supplies. The negative current sensing technique minimizes the impact of the switching noise on the controller operation and offers the user to select the maximum peak voltage across his current sense resistor. Its power dissipation can thus be application optimized.Finally, the bulk input ripple ensures a natural frequency smearing which smooths the EMI signature.

The NCP1360 offers a new solution targeting output power levels from a few watts up to 20 W in a universal-mains flyback application.Thanks to a novel method this new controller saves the secondary feedback circuitry (opto-coupler and TL431 reference) while achieving excellent line and load regulation.The NCP1360 operates in valley lockout quasi-resonant peak current mode control mode at high load to provide high efficiency. When the power on the secondary side starts to diminish, the controller automatically adjusts the duty-cycle then at lower load the controller enters in pulse frequency modulation at fixed peak current with a valley switching detection. This technique allows keeping the output regulation with tiny dummy load. Valley lockout at the first 4 valleys prevent valley jumping operation and then a valley switching at lower load provides high efficiency.

The NCP1362 is a new quasi−resonant peak current mode control mode controller targeting output power levels from a few watts up to 50 W in a flyback application. It is primary side regulated for Constant Voltage and Constant Current regulation, achieving excellent line and load regulation without requiring the typical opto-coupler and voltage reference.

The NCP1365 offer a new solution targeting output power levels from a few watts up to 20 W in a universal-mains flyback application.Thanks to a novel method this new controller eliminates the need for a secondary feedback circuitry (typically an opto-coupler and TL431 reference) while achieving excellent line and load regulation.The NCP1365 operates in valley lockout quasi-resonant peak current mode control mode at high load to provide high efficiency. When the power on the secondary side starts to diminish, the controller automatically adjusts the duty-cycle then at lower load the controller enters in pulse frequency modulation at fixed peak current with a valley switching detection. This technique allows keeping the output regulation with tiny dummy load. Valley lockout at the first 4 valleys prevent valley jumping operation and then a valley switching at lower load provides high efficiency.

NCP137 is a 700 mA LDO equipped with NMOS passtransistor and a separate bias supply voltage (VBIAS). The deviceprovides very stable, accurate output voltage with low noise suitablefor space constrained, noise sensitive applications. In order tooptimize performance for battery operated portable applications, theNCP137 features low IQ consumption. The WLCSP6 1.2 mm x 0.8 mmpackage is optimized for use in space constrained applications.Similar Products:

The NCP1370 is a PWM current mode controller targeting isolatedflyback and non−isolated constant current topologies. The controlleroperates in a quasi−resonant mode to provide high efficiency. Thanksto a novel control method, the device is able to precisely regulate aconstant LED current from the primary side. This removes the needfor secondary side feedback circuitry, biasing and an opto−coupler.The device is highly integrated with a minimum number of externalcomponents. A robust suite of safety protection is built in to simplifythe design. This device supports analog/digital dimming and bothmodes can be combined to enhance dimming precision. The NCP1370has a programmable peak current limit to optimize designcompatibility over a wide range of applications. The controllerfeatures a standby mode with reduced current consumption.

The NCP1380 is a high performance device aimed at powering quasi-resonant converters. Capitalizing on a proprietary valley lockout system, the controller shifts gears and reduces the switching frequency as the power loading becomes lighter. This results in a stable operation despite switching events always triggering in the drain-source valley. This system works down to the 4th valley and toggles to a variable frequency mode beyond, ensuring an excellent standby power performance. To improve the safety in the overload situations, the controller includes an Over Power Protection (OPP) circuit which clamps the delivered power at high-line. Safety-wise, a fixed internal timer relies on the feedback voltage to detect a fault. Once the timer elapses, the controller stops and stays latched for option A and C or enters auto-recovery mode for option B and D. Particularly well suited for adapter applications, the controller features a pin to implement either a combined overvoltage / overtemperature protection (version A and B) or a combined brownout / overvoltage protection (version C and D).

Housed in a SO-14 package, the NCP1382 includes everything needed to build rugged and efficient Quasi-Resonant (QR) Switching Power Supplies. When powered by a front-end Power Factor Correction circuitry, the NCP1382 automatically disconnects the PFC controller in low output loading conditions (with an adjustable level), thus improving the standby power. This is particularly well suited for medium to high power offline applications, e.g. notebook adapters.When the current setpoint falls below a given value, e.g. the output power demand diminishes, the IC automatically enters the so-called skip cycle mode and provides excellent efficiency at light loads. Because this occurs at an adjustable low peak current together with a proprietary Soft-Skip technique, no acoustic noise takes place. Skip cycle also offers the ability to easily select the maximum switching frequency at which foldback and standby take place.The NCP1382 also features several efficient protection options like a) a short-circuit overload detection independent of the auxiliary voltage b) an auto-recovery brown-out detection and c) an input to externally latch the circuit in case of Overvoltage Protection or Over Temperature Protection..NCP1381 vs. NCP1382: Latchoff Level On the Skip Adjustment Pin:NCP1381 3.5 V Typ.NCP1382 2.5 V Typ