STMicroelectronics Manuals

This application note describes how to design a wide range PFC circuit.

The L4973 family is a 3.5A monolithic step-down dc-dc converter, available in POWERDIP18( 12+3+3) and SO20L (12+4+4) plastic packages. The operating input supply voltage range is from 8V to 55V, and the output ranges from 3.3V (L4973D3.3) and 5.1V(L4973D5.1) to 40V. Other regulated outputs below 3.3V are also possible (See Application Note AN938). Using two L4973D is possible to deliver up to 7A with a good sharing between the two sections or a re- dundant 3.5A. The two devices work at a switching frequency of 200kHz. At Vcc = 24V, Vo = 5.1V at 7A the efficiency is 87%. At 3.5A output, the efficiency is 90%.

This is an application note that describes the design of a 90W monitor power supply, including input/output parameters, switching frequency, target efficiency and maximum input power.

This document describes a solution for off-line switch mode power supply (SMPS) using VIPer100-E. The VIPer100-E is a current mode PWM with a 620V / 2.5Ω power switch, capable of withstanding avalanche current during normal operation. This solution is suitable for many applications such as VCRs, TV sets, satellite receivers or decoders, providing customers with a simpler design phase and reduced component count.

This paper provides a model and a tool for evaluating and improving the control loop characteristics of L6561-based PFC preregulators in boost topology and operated in Transition Mode (TM). The model can be used to evaluate the control loop performance of TM PFC preregulators and to optimize the design of TM PFC preregulators.

This application note presents the L4978, a 2A monolithic step-down DC-DC converter. It is realized in BCD60 II technology, and it is available in two plastic packages, MINIDIP and SO16L. One direct fixed output voltage at 3.3V ±1% is available, adjustable for higher output voltage values, till 40V, by an external voltage divider. The operating input supply voltage ranges from 8V to 55V, while the absolute value, with no load, is 60V. New internal design solutions and superior technology performance allow to generate a device with improved efficiency in all the operating conditions and with reduced EMI due to an inno- vative internal driving circuit, and reduced external component counts. While internal limiting current and thermal shutdown are today considered standard protection functions, mandatory for a safe load supply, oscillator with voltage feedforward improves line regulation and overall control loop. Soft-start avoids output overvoltages at turn-on, while, shorting this pin to ground, the device is completely disabled, going into zero consumption state.

This application note explains how to use the VIPER20, ST62 µController, and TSM102A to implement a dual Li-Ion battery charger in an SMPS-type battery charger. It features constant current/constant voltage charging, battery type recognition, precision voltage control, temperature and failing battery protection, and end of charge detection.

This paper describes a flyback converter design method based on L6561, which has good performance and low power consumption characteristics, suitable for medium and low power applications

This application note describes how to design high power factor feedback flyback converters using the L6561.

This document describes how to reduce the power loss of light loaded flyback converters with L5991 controller.

This application note describes how to use the L6561 controller to replace magnetic amplifiers in computer power supplies for secondary regulation.

L4971 is ST company's 1.5A high efficiency DC-DC converter, working in fixed frequency continuous mode. This application note introduces the internal design and application circuits of this device, including power supply voltage, output voltage, limiting circuit, temperature shutdown and other circuit design

AN938 application note describes the design of L4973 3.5A high efficiency DC-DC converter, which uses BCD60 II technology and adopts continuous mode step-down topology. The input voltage range is 8V-55V, and the output voltage is 60V in no-load condition. The internal current limiting and thermal shutdown are considered as standard protection functions for safe load supply, and an oscillator with voltage feed-forward improves line regulation and overall control loop. The soft-start function prevents output overvoltage at turn-on, and the synchronization function can reduce EMI problems in multi-output power supplies. The inhibit function, introduced for power management in equipment having standby features, when active (high), reduces device power consumption by a few tens of µA.

This document introduces the L6561 power converter application. The power converter uses the TM technique to achieve power factor correction, which has high power factor and low harmonics.