Dialog Semiconductor Gmbh

Iwatt Inc.

Dialog Semiconductor (uk) Limited

Jun Zheng

Junjie Zheng

John William Kesterson

Yong Li

Hien Huu Bui

Andrew Kwok-Cheung Lee

Allan Ming-Lun Lin

Carrie Seim

Huaming Guo

Jianming Yao

Liang Yan

Xiaoyan Wang

Yimin Chen

Clarita C Poon

Eng Hwee Quek

Zhaowu Luo

A switch detection circuit is provided that senses the voltage on a rectifying component for rectifying a secondary winding current through a secondary winding of a flyback converter's transformer to determine whether a power switch transistor attached to a primary winding of the transformer has ceased cycling.

Input voltage detection for flyback converter

The drive current of the switch in a switching power converter is adjusted dynamically according to line or load conditions within a switching cycle and/or over a plurality of switching cycles. The magnitude of the switch drive current can be dynamically adjusted within a switching cycle and/or over a plurality of switching cycles, in addition to the pulse widths or pulse frequencies of the switch drive current.

Magnitude adjustment of the drive signal of a switching transistor of a switching power converter

A switching power converter () comprises a transformer () with a parasitic capacitance (), a first switch () coupled to the transformer () and configured to couple or decouple a load () to or from a power source via the transformer (), a switch controller () coupled to the first switch () and configured to generate a switch drive signal () for turning on or off the first switch () according to switching cycles, and a bypass circuit configured to provide a bypass path for the parasitic elements such as the parasitic capacitance (). The bypass circuit may be coupled in parallel with the auxiliary winding (), the primary winding (), or the secondary winding () of the transformer (). High frequency ringing and EMI/RFI is reduced when the bypass circuit is enabled.

Switching power converter for reducing EMI from ring oscillation and its control method

A switching power converter comprises a transformer (), a switch () coupled to the transformer (), and a switch controller () coupled to the switch () for generating a switch drive signal () to turn on or off the switch (). The drive current of the switch drive signal () is adjusted dynamically according to line or load conditions within a switching cycle and/or over a plurality of switching cycles. The magnitude of the drive current can be dynamically adjusted within a switching cycle and/or over a plurality of switching cycles, in addition to the pulse widths or pulse frequencies of the drive current.

Dynamic drive of switching transistor of switching power converter

A controller of an AC/DC flyback switching power supply uses adaptive digital control approaches to control the switching operation of a BJT power switch based on primary-side feedback to regulate the secondary-side constant output voltage and output current, without using the input line voltage. Switching-cycle by switching-cycle peak current control and limit are achieved based on the sensed primary-side current rather than the input line voltage in both constant-voltage and constant-current modes, operating in PWM, PFM and/or combinations of a plurality of PWM and PFM modes. The controller IC does not need a separate pin and ADC circuitry for sensing the input line voltage. The controller IC directly drives the BJT base, and dynamically adjusts the BJT base current amplitude cycle by cycle based on load change.

Controller for switching power converter driving BJT based on primary side adaptive digital control

A switching power converter detects low load conditions based on the ratio of a first peak current value for peak current switching in constant voltage regulation mode to a second peak current value for peak current switching in constant current regulation mode. The power supply load is considered to have a low load if the ratio is lower than a predetermined threshold. Once a low load condition is detected, the switching frequency of the switching power converter is reduced to a level that minimizes switching loss in the power converter. In addition, the switching power converter also adjusts the switching frequency according to the sensed input line voltage. An offset is added to the switching period to reduce the switching frequency of the switching power converter, as the input line voltage is increased.

Detecting light load conditions and improving light load efficiency in a switching power converter

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Shenzhen, China

Jun Zheng