Other

Qi Cui Wei

Da Feng Weng

Xiao Song

Zong Bing Li

In order to keep the advantage of PWM dimming control scheme and make the LED driver high reliability and the LED lamp long lifetime, it is required that the frequency of PWM dimming control scheme is related with or the same as the output frequency of existed dimmers; and the output PWM dimming pulse is covered by the output pulse from dimmers further. The present invention discloses a novel 'LED dimming control' scheme to make that the frequency of PWM dimming control scheme is related with or the same as the output frequency of dimmers; and the output PWM dimming pulse is covered by the output pulse from the dimmers further. In this way, it can guarantee that as PWM dimming pulse comes, the output from the dimmer can offer enough power to the LED driver and the LED driver can output the required LED driving current without flicker.

LED dimming control scheme

A switching adapter control method for adaptive mobile power systems is composed of reference current generator, current mode error compensator, controllable constant turn-off timer, PWM generator and MOSFET driver. The output of the switching adapter can show constant current and voltage characteristics, that means, as the DC bus voltage is over a preset voltage, the adaptor's output characteristic is converted from a constant current source into a constant voltage source with the preset voltage. For low output capacitance case, the present invention has the ability to smoothly reduce the switching frequency of the switching adaptor and reduce the switching losses and meet Energy Star 2.0 requirements under different load conditions. And the output ripple current and voltage can be in the allowed range.

Switching adapter control method for adaptive mobile power systems

High accuracy average output current control scheme for power current converter in critical DCM is composed of the reference block to generate preset reference; the reference calculation block, based on the power current converter's power topology, the correspondent algorithm is calculated to convert the input reference into correspondent output; the state detecting block, the states of power current converter are detected and the detected signals are converted into the same signal format as one of output from reference calculation block; the error detector is used to detect the error between the outputs from reference calculation block and state detected block and to trigger power driver block to turn off the power switch in the power current converter as the error is cross over zero; the zero state detector is used to detect when the states of the power current converter are cross over zero and trigger power driver block to turn on the power switch in the power current converter; the power driver block is controlled with both the error detector and the zero state detector to drive the power switch in the power current converter; based on the correspondent algorithm, the output of power driver block may be used for synchronizing calculation. With the invented control scheme, it makes the accuracy of average output current of the power current converter independent of input and output voltages, circuit devices accuracy of the power current converter, and makes the average output current in high accuracy control, control scheme implement in simple and low cost.

Growing community of inventors

Hangzhou, China

Qi Cui Wei