Xmems Labs, Inc.

Hung-Chi Huang

Jemm Yue Liang

Chieh-Yao Chang

Hsi-Sheng Chen

Jing-Meng Liu

A feedback control system configured to drive a load is disclosed. The feedback control system includes an up-sampling circuit, configured to perform an un-sampling operation on a source signal and produce an up-sampled signal with an up-sampling frequency according to the up-sampled signal and a feedback signal from the load; a delta circuit, coupled to the up-sampling circuit and configured to produce a delta signal; a sigma circuit, configured to produce a density modulation signal according to the delta signal; and a driving device, configured to drive the load according to the density modulation signal with the up-sampling frequency.

Feedback control system achieving high performance via density modulation

A method is applied in a controller within a driving circuit comprising a driving sub-circuit configured to drive a load. The method comprises steps of: performing a table learning operation on a table at least at a first rate during a learning period; and performing the table learning operation on the table at a second rate lower than the first rate after the learning period; wherein the table is stored in a memory within the controller. The table learning operation comprises steps of: receiving a first feedback signal from the load corresponding to a first cycle; obtaining a control code from the table according to the first feedback signal; generating a control signal according to the control code; receiving a second feedback signal from the load corresponding to the second cycle; and updating the control code and saving the updated control code back to the table in the memory.

Method of table learning with reduced learning rate applied in driving circuit and driving circuit using the same

A method is applied in a pulse width modulation (PWM) controller within a driving circuit including a bidirectional circuit coupled to a load. The method includes steps of: obtaining a pulse width control code (PWCC) from a table stored in a memory within the PWM controller according to a difference between a first feedback signal from the load and an input signal, wherein the PWCC is corresponding to an intended voltage difference, and the first feedback signal is corresponding to a first cycle; generating a plurality of PWM signals according to the PWCC, wherein during a second cycle the bidirectional circuit performs a charging or discharging operation on the load according to the PWM signals; receiving a second feedback signal from the load corresponding to the second cycle; and updating the PWCC according to the first and second feedback signals, and saving the updated PWCC back to the table.

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Taoyuan, Taiwan

Hung-Chi Huang