Current detecting circuit, load drive, and storage

A current detection circuit and current detection technology, applied in measurement devices, measurement of current/voltage, measurement of electrical variables, etc., can solve problems such as power efficiency reduction, current detection resistance loss, inability to detect load current, etc., to reduce power consumption. Effect

Inactive Publication Date: 2007-02-28
ROHM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In the current detection circuits of the conventional patent documents 1 and 2, since the loss due to the current detection resistor always occurs, the power efficiency is lowered.
Moreover, when the load is driven by PWM in a load drive circuit composed of a bridge circuit, current detection cannot be performed during

Method used

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  • Current detecting circuit, load drive, and storage
  • Current detecting circuit, load drive, and storage
  • Current detecting circuit, load drive, and storage

Examples

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Embodiment Construction

[0055] Embodiments of a current detection circuit, a load drive circuit using the current detection circuit, and a storage device having a motor driven by the load drive circuit according to the present invention will be described below with reference to the drawings.

[0056] Fig. 1 shows a current detection circuit of the first embodiment. Since the load is driven by this current detection circuit, the current detection circuit in FIG. 1 may also be called a load drive circuit or a load drive device.

[0057] In FIG. 1, a P-type MOS transistor 11 as a first transistor is connected in series with a load 50 and connected to a first power supply voltage V CC and between. The first transistor 11 is turned on when a switching signal S1 (L level) as a control signal is applied to the gate, and a load current (output current) I1 flows. In addition, unless otherwise specified in this specification, a voltage means a potential with respect to a ground voltage.

[0058] Since the s...

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Abstract

A current detecting circuit for stably detecting the current flowing through a load at all times with high accuracy by greatly reducing the power loss due to the detection of the current. The power supply voltage and a switch signal are supplied commonly to a power transistor and a current detecting transistor. An idling current is supplied to the output node of the current detecting transistor. A buffer circuit is provided so that the output voltages of both transistors may be the same virtual potentials. As a result, the buffer circuit is operated as a class-A amplifier circuit at all times.

Description

technical field [0001] The present invention relates to a current detection circuit that stably and accurately detects the current flowing in a load such as a spindle motor for storage devices such as HDDs and FDDs, a load drive circuit using the current detection circuit, and a device with a load drive circuit driven by the load drive circuit. storage device for the motor. Background technique [0002] As a current detection circuit for detecting the current flowing in a load driven by a transistor, etc., a current detection resistor is connected in series to the transistor or the load, and the current is directly detected by the voltage drop caused by the current detection resistor. Generally, the current The detection circuit is used as disclosed in JP-A-11-299292 (hereinafter referred to as Patent Document 1) or JP-A-2003-174766 (hereinafter referred to as Patent Document 2). [0003] Furthermore, there is known a current detection circuit disclosed in Japanese Patent N...

Claims

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Application Information

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IPC IPC(8): G01R19/00G01R19/165
Inventor 杉江尚笹本裕
Owner ROHM CO LTD
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