Load Driving Device and Electrical Device Using the Same

a technology of driving device and electrical device, applied in the direction of electric motor speed/torque regulation, instruments, signalling systems, etc., can solve the problems of large heat generation, easy burnout, and failure to detect overcurrent,

Inactive Publication Date: 2010-07-29
ROHM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a load driving device that can prevent load burnout. The device includes a current generation section, an integration section, a comparison section, and an output section. The device generates a first current based on the driving current of the load and a predetermined second current. The integration section charges and discharges a capacitor based on the relationship between the first current and the second current. The comparison section compares the terminal voltage of the capacitor with a predetermined threshold voltage. The output section generates a protection signal based on the output logic of the comparison section. This device can protect the load from overcurrent or overvoltage.

Problems solved by technology

The actuator coil for a pickup lens described above, although being a light, small component, is driven by flow of a relatively large current, and thus generates large heat and is easy to burn out.
However, with the technique of muting all coil outputs when a maximum output of the actuator coil is detected continuously for a certain period of time, overcurrent is not detected in a case where driving is continued immediately before the maximum output of the actuator coil, thus causing a risk of occurrence of burnout.
With the technique of monitoring a power current of a driver driving a plurality of actuator coils to thereby control a peak current, a risk of failure to detect overcurrent arises when there is bias in the driving current of each actuator coil.
With the technique of detecting a control signal of a driver with a DSP (Digital Signal Processor) in a software-based manner to thereby control a peak current, a driving current is indirectly detected, which results in an increase in variation in the driving current to a coil due to variation in a coil and a driver driving signal, thus causing a risk of failure to detect overcurrent with high accuracy.

Method used

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  • Load Driving Device and Electrical Device Using the Same
  • Load Driving Device and Electrical Device Using the Same
  • Load Driving Device and Electrical Device Using the Same

Examples

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Embodiment Construction

[0023]Hereinafter, detailed description will be given, referring to a case where the present invention is applied to a motor driver IC loaded in an optical disc driving device.

[0024]FIG. 1 is a block diagram showing one embodiment of the optical disc driving device according to the invention.

[0025]As shown in this figure, the optical disc driving device of this embodiment has a motor driver IC1, loads 2, a digital signal processor 3 (hereinafter, referred to as DSP (Digital Signal Processor) 3), a microcomputer 4, and a memory 5.

[0026]The motor driver IC1 includes: a focus servo driver circuit 11, a tracking servo driver circuit 12, a spindle motor driver circuit 13, a thread motor driver circuit 14, and a loading motor deriver circuit 15. The motor driver IC1 is a multi-channel load driving device that supplies driving currents respectively to a plurality of loads 2 (a focus servo coil 21, a tracking servo coil 22, a spindle motor 23, a thread motor 24, and a loading motor 25) base...

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Abstract

A load driving device according to the present invention includes: a first current generation section generating a first current in accordance with a driving current of a load; a second current generation section generating a predetermined second current; an integration section charging and discharging a capacitor in accordance with magnitude relation between the first current and the second current; a comparison section comparing a terminal voltage of the capacitor and a predetermined threshold voltage; and an output section generating a protection signal based on output logic of the comparison section. Such configuration permits appropriately preventing load burnout.

Description

[0001]This application is based on Japanese Patent Application No. 2006-272775 filed on Oct. 4, 2006, the contents of which are hereby incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a load driving device for supplying a driving current to a load and an electrical device (for example, an optical disc driving device) using such a load driving device.[0004]2. Description of Related Art[0005]In a car navigation system, a car audio system, or a portable navigation system including an optical disc driving device that performs recording and reproduction on an optical disc such as a DVD (Digital Versatile Disc), a CD (Compact Disc), an MD (Mini Disc), or the like, a beam spot is formed on the recording surface of the optical disc by using a pickup lens to thereby perform data recording and reproduction on the optical disc. As an actuator for making fine adjustment of an optical pickup position, a focus coil, a track...

Claims

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Application Information

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Patent Type & AuthorityApplications(United States)
IPC IPC(8): G08B7/00H02H3/00H02H7/00H02P5/00
CPCH02H7/093H02H7/0838
InventorYAMAMOTO, SEIICHIOTA, TAKAHIRO
OwnerROHM CO LTD