What is pulse width modulation (PWM)?
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Pulse Width Modulation (PWM) is a way of digitally encoding analogue signal levels. Through the use of high-resolution counters, the duty cycle of a square wave is modulated to encode a specific analogue signal level. In more general terms, a switch is opened and closed in timed pulses, where the time the switch is closed is determines the power output. Basically, a PWM variable-power scheme switches the power quickly between fully ON and fully OFF tens or hundreds of kHz in the case of a computer power supply (which has a regulated output). The switching rate is much faster than what would affect the load. The term duty cycle describes the proportion of ON time to the regular interval or period of time. A low duty cycle corresponds to low power because the power is off for most of the time. Duty cycle is expressed in percent, 100% being fully ON. |
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| 2004-05-04 | Character LCD interface for the Z8 Encore! This app note provides character LCD driver routines, coded in ANSI C, for the Z8 Encore! Flash MCU-based embedded software. |
| 2004-06-16 | Intro to timer-based measurement This article will explain how to use input capture timers to measure quantities from devices such as ADCs and encoders, and the issues you have to consider when using timers in this way which are range, accuracy, sampling rate and drift. |
| 2004-06-17 | LM5025 active clamp voltage mode PWM controller LM5025 active clamp voltage mode PWM controller |
| 2004-06-17 | LM5020 100V current mode PWM controller LM5020 100V current mode PWM controller |
| 2004-07-16 | Selecting and designing a LED driver The article analyzes the choices, constraints and trade-offs on selecting white LED drivers for portable consumer devices. |
| 2004-11-16 | Audio power amplification goes beyond Class D Switching amplifiers with wideband performance and low distortion require innovations beyond basic Class D circuit topology. |
| 2004-12-01 | Designing for high efficiency with the active clamp UCC2891 PWM controller Designing for high efficiency with the active clamp UCC2891 PWM controller |
| 2004-12-01 | 200W interleaved forward converter design review using TI's UCC28221 PWM controller 200W interleaved forward converter design review using TI's UCC28221 PWM controller |
| 2004-12-15 | Speed error in PWM fan control systems Speed error in PWM fan control systems |
| 2004-12-16 | Using cost-effective PWM controller for small power-offline apps Using cost-effective PWM controller for small power-offline apps |
| 2005-01-17 | MCU, flash enhance battery charger features Find out the advantages of using an 8bit flash MCU in designing offline Li-ion battery chargers. |
| 2005-03-01 | Changing MCU technologies for motor control A different MCU application may just be able to provide the energy-saving capacity needed for home, industrial and automotive motors. |
| 2005-06-02 | Class D audio amplifier basics This app note explains the Class D audio amplifier, which is basically a switching |
| 2005-06-03 | Using the ISL6420 PWM controller evaluation board Using the ISL6420 PWM controller evaluation board |
| 2005-06-17 | A simple circuit for driving microcontroller friendly PWM generators A simple circuit for driving microcontroller friendly PWM generators |
| 2005-06-20 | Implementing constant current constant voltage ac adapter by NCP1200 and NCP4300A This app note describes a compact design of constant current constant voltage (CCCV) ac adapter based on the current mode PWM controller NCP1200 and the secondary side feedback IC NCP4300A. |
| 2005-06-21 | Design of a 100W dc-dc converter for telecom systems using the NCP1560 This app note discusses the NCP1560 PWM controller that contains all the features and flexibility needed to implement voltage-mode control for single-ended dc-dc converters |
| 2005-08-01 | DC/DC integration cuts space, time Integrating a DC/DC switching converter requires compact, multiple point-of-load power supplies and offers transient response to dynamic loads |
| 2005-10-03 | Next-gen cellphones cry for more power Handset designers must consider several factors to effectively conserve power and extend battery life |
| 2005-10-17 | Filterless amp saves PCB space, power The choice of power amplifier can impact power consumption in today's mobile devices |
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