Invention Grant
- Patent Title: VCM driver and PWM amplifier
- Patent Title (中): VCM驱动器和PWM放大器
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Application No.: US12728449Application Date: 2010-03-22
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Publication No.: US07848044B2Publication Date: 2010-12-07
- Inventor: Yasuhiko Kokami , Hiroshi Kuroiwa
- Applicant: Yasuhiko Kokami , Hiroshi Kuroiwa
- Applicant Address: JP Kawasaki
- Assignee: Renesas Electronics Corporation
- Current Assignee: Renesas Electronics Corporation
- Current Assignee Address: JP Kawasaki
- Agency: Mattingly & Malur, P.C.
- Priority: JP2007-243662 20070920
- Main IPC: G11B5/02
- IPC: G11B5/02 ; G11B21/02

Abstract:
The present invention provides a VCM driver realizing low power consumption and high accuracy and a PWM amplifier compensating a dead time distortion. A phase compensator, a ΔΣ modulator receiving an output signal of the phase compensator and converting the output signal to a control code of predetermined bits, a PWM modulator receiving the control code to produce a PWM signal, and an output circuit receiving the PWM signal to drive a voice coil constitute a forward path. A sense amplifier sensing a current of the voice coil, an ADC receiving an output signal of the sense amplifier, a low-pass filter receiving an output signal of the ADC, and a decimation filter receiving an output signal of the low-pass filter constitute a feedback path. An output signal of the decimation filter is fed back to the input side of the phase compensator to form a major feedback loop having a first-order characteristic loop gain. An output signal of the decimation filter is fed back to the output side of the phase compensator to form a minor feedback loop having a loop gain which is flat until a target band frequency when viewed from the output side of the phase compensator.
Public/Granted literature
- US20100177444A1 VCM DRIVER AND PWM AMPLIFIER Public/Granted day:2010-07-15
Information query
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