JP2005209039A - Power supply circuit and optical disk device equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide stable voltage to a plurality of elements on an electronic circuit by using a linear regulator from a DC power supply and to reduce its power consumption. <P>SOLUTION: The plurality of elements 202 to 204 are divided into two groups, in each of which at least more than one element exists. One of the groups is an upper section group and the element 202 is inserted between the DC power supply 205 and an output terminal of the linear regulator 201; the other group is a lower section group and the respective elements 203 and 204 are inserted between the output terminal of the linear regulator 201 and a GND. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a power supply circuit using a linear regulator and an optical disk apparatus (optical disk drive) including the same.

In order to supply a stable voltage to each element on an electronic circuit, a voltage regulator circuit (IC) called a linear regulator is widely used.
7 shows a general connection relationship between the linear regulator 101 and each of the elements 102, 103,.
When a voltage supplied from the DC power supply 104 is input to the input terminal of the linear regulator 101, a predetermined voltage obtained by dropping the input voltage (Vin) is stably output from the output terminal. This output voltage (Vout) drives the elements 102 and 103 connected in parallel between the output terminal of the linear regulator 101 and GND.

However, the linear regulator has a small external circuit and a clean output, but has a power loss.
That is, a power supply circuit using the above-described linear regulator consumes a considerable amount of power. Moreover, this power consumption is a loss that appears in a wasteful form of heat generated by the linear regulator linear. This power consumption in the linear regulator is expressed by multiplying the output current by the voltage difference between the input and output. Therefore, in the case of the connection-related power supply circuit shown in FIG. If the current consumption flowing through I is I1, I2,..., The power consumption P is P = (Vin−Vout) × Iout = (Vin−Vout) × (I1 + I2 +...). That is, it can be seen that power consumption increases according to the number of elements (as much as the number of elements increases) and according to current consumption in each element (as much as the current consumption increases).

Similarly, there is a power supply circuit for supplying a stable voltage, which is called a switching regulator, but this causes noise in the output although power loss is small. That is, a large amount of noise is generated at the time of switching, which is not suitable for a circuit that handles minute analog signals. In addition, it is necessary to provide many external circuits (such as a circuit for determining an output voltage and a circuit for reducing noise), and the power supply circuit becomes complicated and large.
Furthermore, conventionally, only one device having the same voltage required for driving can be connected to one regulator.

  The present invention has been made in view of the above problems, and can supply a stable voltage to a plurality of elements on an electronic circuit using a linear regulator from a DC power supply, and reduce the power consumption. With the goal.

The present invention provides a power supply circuit that supplies a stable voltage to a plurality of elements on an electronic circuit using a DC power supply and a linear regulator, and is characterized as follows in order to achieve the above object. To do.
In the power supply circuit according to the first aspect of the present invention, the plurality of elements are divided into two groups, and each group includes at least one element. Is inserted (connected) between the DC power supply and the output terminal of the linear regulator, and the other group is set as a lower group, and each element is inserted between the output terminal of the linear regulator and GND. Is.

A power supply circuit according to a second aspect of the present invention is the power supply circuit according to the first aspect, wherein the total current consumption of the elements belonging to the upper group is equal to the total current consumption of the elements belonging to the lower group. The plurality of elements are divided into the upper group and the lower group.
According to a third aspect of the present invention, there is provided a power supply circuit according to the first or second aspect, wherein a level shift circuit is interposed between the element belonging to the upper group and the element belonging to the lower group, and the upper stage When a signal output from one of the elements belonging to the group and the element belonging to the lower group is input to the other element, the voltage level of the signal is changed by the level shift circuit.

  According to a fourth aspect of the present invention, there is provided the power supply circuit according to the first or second aspect, wherein an AC couple is interposed between the element belonging to the upper group and the element belonging to the lower group, and the upper group. When a signal output from one of the elements belonging to the above and the elements belonging to the lower group is input to the other element, the voltage level of the signal is changed by the AC couple.

According to a sixth aspect of the present invention, there is provided the power supply circuit according to the first aspect, wherein the total current consumption of the elements belonging to the lower group is larger than the total current consumption of the elements belonging to the upper group. In addition, the plurality of elements are divided into the upper group and the lower group.
An optical disc apparatus according to a seventh aspect of the invention includes the power supply circuit according to any one of the first to sixth aspects.

  According to the power supply circuit and the optical disk apparatus of the present invention, when a voltage is supplied from a DC power supply to a plurality of elements on an electronic circuit using a linear regulator, a current flowing from the linear regulator to the element is reduced ( Because the linear regulator uses less current, the linear regulator can be used to supply a stable voltage to multiple elements on the electronic circuit and reduce its power consumption. it can.

Hereinafter, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
First, a configuration example of an optical disc apparatus provided with a power supply circuit embodying the present invention will be described with reference to FIG.
FIG. 2 is a block diagram showing an example of the configuration of an optical disc apparatus for carrying out the present invention.
The optical disk device 20 includes a spindle motor 22, an optical pickup device 23, a laser control circuit 24, an encoder 25, a motor driver 27, a reproduction signal processing circuit 28, a servo controller 33, a buffer RAM 34, a buffer manager 37, an interface 38, a ROM 39, and a CPU 40. , RAM 41, flash memory 42, and power supply circuit including linear regulator 201.

In this embodiment, the optical disc apparatus 20 is built in a PC (personal computer) main body 300, but may be built in another information processing apparatus main body such as a WS (workstation) main body, It can also be externally attached to various information processing apparatus bodies such as the WS body.
Note that the arrows in FIG. 2 indicate the flow of typical signals and information, and do not represent the entire connection relationship of each block.
The optical disk 15 is a computer-readable recording medium such as a write once or rewritable MO, CD-R, CD-RW, DVD + R, DVD + RW, DVD-R, DVD-RW, DVD-RAM.

The spindle motor 22 is for rotating the optical disk 15 as an information recording medium.
The optical pickup device 23 is a semiconductor laser as a light source, an optical system that guides the light beam emitted from the semiconductor laser to the recording surface of the optical disc 15 and guides the return light beam reflected by the recording surface to a predetermined light receiving position, The light receiving device is arranged at a light receiving position and receives a return light beam, and a driving system (focusing actuator, tracking actuator, and seek motor) (not shown) and the like. The light receiver outputs a current (current signal) corresponding to the amount of received light to the reproduction signal processing circuit 28.

  The reproduction signal processing circuit 28 includes an I / V amplifier, a servo signal detection circuit, a wobble signal detection circuit, an RF signal detection circuit, an ATIP decoder, a CD decoder, a CD-ROM decoder, a D / A converter, etc. (not shown). Yes. The I / V amplifier converts a current signal that is an output signal of the optical pickup device 23 into a voltage signal, and further amplifies it. The servo signal detection circuit detects a servo signal (focus error signal or track error signal) based on the voltage signal from the I / V amplifier and outputs it to the servo controller 33. The wobble signal detection circuit detects a wobble signal based on the voltage signal from the I / V amplifier. The ATIP decoder extracts ATIP information and a synchronization signal from the wobble signal. The ATIP information extracted here is output to the CPU 40 and the synchronization signal is output to the encoder 25. The RF signal detection circuit detects an RF signal including reproduction information based on the voltage signal from the I / V amplifier. The CD decoder performs error correction processing on the RF signal. The CD-ROM decoder further performs error correction processing and the like on the signal from the CD decoder, and then stores it in the buffer RAM 34 via the buffer manager 37. In the case of music data, a signal from the CD decoder is output to an external audio device or the like via a D / A converter.

The servo controller 33 generates a control signal for controlling the focusing actuator of the optical pickup device 23 based on the focus error signal, and generates a control signal for controlling the tracking actuator of the optical pickup device 23 based on the track error signal. Both control signals are output from the servo controller 33 to the motor driver 27.
The motor driver 27 drives the focusing actuator and tracking actuator of the optical pickup device 23 based on the control signal from the servo controller 33. Further, based on an instruction from the CPU 40, the spindle motor 22 is controlled so that the linear velocity of the optical disk 15 is constant. Further, based on an instruction from the CPU 40, the seek motor of the optical pickup device 23 is driven to control the position of the optical pickup device 23 in the sledge direction (radial direction of the optical disk 15).

Based on an instruction from the CPU 40, the encoder 25 takes out the data stored in the buffer RAM 34 via the buffer manager 37, adds an error correction code, and creates recording data on the optical disc 15. Based on an instruction from the CPU 40, the recording data is output to the laser control circuit 24 in synchronization with the synchronization signal from the reproduction signal processing circuit 28.
The laser control circuit 24 controls the output of the semiconductor laser of the optical pickup device 23 based on the recording data from the encoder 25.
The interface 38 is a bidirectional communication interface with the PC main body 300 and conforms to a standard interface such as ATAPI and SCSI.

The ROM 39 stores a program including an information recording control program described by a code readable by the CPU 40.
The flash memory 42 is a non-volatile memory that can be written to and read from the CPU 40 and retains recorded contents even when the power is shut off (even when the voltage supply from the DC power supply 205 is stopped). Is done.
The CPU 40 controls the operation of each unit according to the program stored in the ROM 39 and temporarily stores data necessary for control in the RAM 41. When the optical disk device 20 is turned on (voltage supply from the DC power supply 205 is started), the program stored in the ROM 39 is loaded into the main memory (not shown) of the CPU 40.

Here, in this embodiment, two different voltages of +12 V and +5 V are supplied to the optical disc apparatus 20 from the DC power source 205 in the PC main body 300. + 12V is supplied only to the motor driver 27. + 5V is supplied to mechanical parts such as the spindle motor 22 and a part of a circuit (IC) that handles analog signals, but is not supplied to a circuit that handles digital signals. + 5V is stepped down to + 2.5V (may be other voltage such as + 3.3V or + 1.8V) by the linear regulator 201, and then supplied to a part of the circuit that handles analog signals and a circuit that handles digital signals. The
Note that the laser control circuit 24 and the reproduction signal processing circuit 28 surrounded by a solid line in FIG. 2 are circuits that handle analog signals, and are configured by one LSI. The encoder 25, the servo controller 33, the CPU 40, and the RAM 41 are circuits that handle digital signals, and are configured by a single LSI.

Next, a power supply circuit including the linear regulator 201 of FIG. 2 will be described.
This power supply circuit uses a DC power supply 205 and a linear regulator 201 to supply a stable voltage to a plurality of elements on an electronic circuit. The plurality of elements (such as the LSI described above) are divided into two groups. In each group, at least one element is present, one of which is an upper group, and each element is interposed between the DC power supply 205 and the output terminal of the linear regulator 201 ( The other group is the lower group, and each element is interposed between the output terminal of the linear regulator 201 and GND.

In this power supply circuit, the current consumed by the upper group is the sum of the current consumed by each element belonging to the upper group. The same applies to the lower group.
In this way, the current supplied by the linear regulator 201 is the difference between the total current consumption of the upper group and the total current consumption of the lower group, and all the elements are connected between the output terminal of the linear regulator 201 and GND as before. Since the power consumption is reduced as compared with the case of insertion (connection) in parallel, power consumption can be reduced.
Here, since the current supplied from the linear regulator 201 can be reduced as the difference in the total current consumption is smaller, this point is taken into consideration when the elements are grouped. That is, the elements are divided into the upper group and the lower group so that the total current consumption of the elements belonging to the upper group is equal to the total current consumption of the elements belonging to the lower group. If it does so, the effect of reducing power consumption can be heightened more.

  However, in this configuration, the reference voltage level of the element belonging to the upper group is the output voltage level of the linear regulator 201, and the reference voltage level of the element belonging to the lower group is the GND level, and there is a difference in the reference voltage level between the groups. Therefore, the elements belonging to the upper group and the elements belonging to the lower group operate with different driving voltages. From this, it can be seen that one linear regulator 201 is connected to a plurality of elements having different voltages required for driving.

In addition, since there is a difference in the reference voltage level between each group, when a signal output from an element belonging to one of the groups is input to an element belonging to the other group and used, the element belonging to each group When a signal output from an element belonging to one of the groups is input to the other element by interposing (connecting) a circuit such as a level shift circuit or AC coupling (AC coupling) between them, the voltage of the signal The level needs to be changed using the circuit (shifted according to the difference in the reference voltage level).
In addition, it is necessary to divide a plurality of elements into an upper group and a lower group so that the total current consumption of elements belonging to the lower group becomes larger than the total current consumption of elements belonging to the upper group. In this way, current backflow can be prevented.

FIG. 1 is a circuit diagram showing a configuration example of a power supply circuit including the linear regulator 201 of FIG. In FIG. 1, for simplicity of explanation, the number of elements on the electronic circuit is three, but it is obvious that the explanation can be made in the same manner even if the number changes.
In the power supply circuit shown in FIG. 1, the VDD terminal (digital power supply terminal) of the element 202 (which may be a plurality of elements) belonging to the upper group is a + 5V DC power supply 205 and the VSS terminal (GND terminal) is the linear regulator 201. Connected to the output terminal, the VDD terminal of each element 203, 204 (one may be three or more elements) belonging to the lower group is used as the output terminal of the linear regulator 201, and the VSS terminal is used as a reference for the potential in the circuit. Are connected to GND.

The linear regulator 201 drops + 5V, which is a voltage input from the Vin terminal, to + 2.5V and supplies it stably from the Vout terminal.
The drive voltage of the element 202 is +2.5 (actually +2.5 to +5 V), and the consumption current I1 is 200 mA.
The drive voltage of the element 203 is +2.5 (actually 0 to +2.5 V), and the consumption current I2 is 100 mA.
The drive voltage of the element 204 is +2.5 (actually 0 to +2.5 V), and the consumption current I3 is 200 mA.

In the power supply circuit configured as described above, the current Iout supplied from the linear regulator 201 is Iout = (I2 + I3) −I1 = 100 mA.
Therefore, the power consumption P of the linear regulator 201 is P = (Vin−Vout) × Iout = 2.5 V × 0.1 A = 0.25 W.
If the above-described elements 202 to 204 are connected as in the conventional power supply circuit shown in FIG. 7, Iout = I1 + I2 + I3 = 500 mA, and P = 2.5 V × 0.5 A = 1.25 W. Therefore, in the power supply circuit according to the present invention shown in FIG. 1, the power consumption can be reduced by 1 W.

As described above, by using the power supply circuit of FIG. 1, a stable voltage can be supplied from the DC power supply 205 to a plurality of elements on the electronic circuit using the linear regulator 201 and the power consumption can be reduced. Can do.
In addition, since the total current consumption of the elements 203 and 204 belonging to the lower group is larger than the current consumption of the element 202 belonging to the upper group, the current does not flow backward.
Depending on the number of elements connected to the power supply circuit, etc., the total current consumption of the elements belonging to the upper group and the total current consumption of the elements belonging to the lower group are equal (or the difference is minimized). In this way, each element can be divided into an upper group and a lower group, so that power consumption can be more efficiently reduced.

Further, in the power supply circuit shown in FIG. 1, the element 202 belonging to the upper group actually operates between 2.5V to 5V, and the elements 203 and 204 belonging to the lower group operate between 0 to 2.5V. (Drive).
Therefore, the drive voltages of the element 202 belonging to the upper group and the elements 203 and 204 belonging to the lower group may be the same or different.
Further, since there is a difference in the reference voltage level between the groups, when a signal output from the element 202 belonging to the upper group is input to the element 204 belonging to the lower group and used, the elements 202, A level shift circuit or an AC couple is inserted between 204, and a power supply circuit including these circuits will be specifically described below.

FIG. 3 is a circuit diagram showing another configuration example of the power supply circuit including the linear regulator 201 of FIG. 2. The same parts as those of FIG.
FIG. 4 is a diagram showing a configuration example of the level shift circuit 206 in FIG. 3 and an example of waveforms of its input / output voltages.
The power supply circuit shown in FIG. 3 is obtained by adding a level shift circuit 206 to the power supply circuit shown in FIG. Specifically, for example, a level shift circuit 206 having the configuration shown in FIG. 4 is inserted between the elements 202 and 204. In this case, since the signal (Vin) output from the upper group is input to the level shift circuit 206, the output (Vout) is used in the lower group.

Here, the element 202 in the upper group is driven at + 2.5V to + 5V, and the reference voltage is Vref1 = 3.75V. The lower group elements 203 and 204 are driven at 0V to + 5V, and the reference voltage is Vref2 = 1.25V.
In the power supply circuit shown in FIG. 3, the level shift circuit 206 of FIG. 4 is inserted between the elements 202 and 204, so that both the alternating current component and the direct current component of the input signal (Vin) are stored, and its waveform Is directly shifted from the 3.75V center to the 1.25V center. That is, from the element 202 belonging to the upper group to the lower group according to the difference between the reference voltage level (3.75 V) of the element 202 belonging to the upper group and the reference voltage level (1.25 V) of the element 204 belonging to the lower group. The voltage level of the signal input to the element 204 to which it belongs is shifted (changed).
Use of such a level shift circuit 206 is effective for any signal. When the DC component is important, or when only a DC signal is output from the element 202 belonging to the upper group, it is necessary to use the level shift circuit 206.

FIG. 5 is a circuit diagram showing still another configuration example of the power supply circuit including the linear regulator 201 of FIG. 2. The same parts as those in FIG.
FIG. 6 is a diagram illustrating a configuration example of the AC couple 207 in FIG. 5 and an example of waveforms of its input / output voltages.
The power supply circuit shown in FIG. 5 is obtained by adding an AC couple 207 made of a capacitor or the like to the power supply circuit shown in FIG. Specifically, for example, an AC couple 207 having the configuration shown in FIG. 6 is inserted between the elements 202 and 204. In this case, since the signal (Vin) output from the upper group is input to the AC couple 207, the output (Vout) is used in the lower group.

In this power supply circuit, the AC couple 207 of FIG. 6 is inserted between the elements 202 and 203, whereby the AC component of the input signal (Vin) is preserved, but the DC component is not passed. The output waveform approaches the center of 1.25V.
Such an AC couple 207 is simpler and cheaper than the level shift circuit described above, but can be used only when the DC voltage level of the signal output from the element 202 is not important for the operation of the element 204.

  The present invention can be applied to a power supply circuit using a linear regulator and an optical disk apparatus including the power supply circuit.

FIG. 3 is a circuit diagram illustrating a configuration example of a power supply circuit including the linear regulator 201 of FIG. 2. It is a block diagram which shows the structural example of the optical disk apparatus which implements this invention. FIG. 3 is a circuit diagram showing another configuration example of the power supply circuit including the linear regulator 201 of FIG.

FIG. 4 is a diagram illustrating a configuration example of a level shift circuit 206 in FIG. FIG. 6 is a circuit diagram showing still another configuration example of a power supply circuit including the linear regulator 201 of FIG. 2. FIG. 6 is a diagram illustrating a configuration example of an AC couple 207 in FIG. 5 and an example of waveforms of input / output voltages thereof. It is a figure which shows the general connection relation of a linear regulator and each element.

Explanation of symbols

20: Optical disk device 201: Linear regulator 202-204: Element 205: DC power supply 206: Level shift circuit 207: AC couple

Claims (7)

In a power supply circuit that uses a DC power supply and a linear regulator to supply a stable voltage to multiple elements on an electronic circuit,
Dividing the plurality of elements into two groups, each group having at least one element;
One of them as the upper group, each element is inserted between the DC power supply and the output terminal of the linear regulator,
A power supply circuit, wherein the other group is a lower group, and each element is interposed between the output terminal of the linear regulator and GND. The power supply circuit according to claim 1,
The plurality of elements are divided into the upper group and the lower group so that a total value of current consumption of elements belonging to the upper group is equal to a total value of current consumption of elements belonging to the lower group. Power supply circuit. The power supply circuit according to claim 1 or 2,
A level shift circuit is interposed between the element belonging to the upper group and the element belonging to the lower group, and the signal output from one element of the element belonging to the upper group and the element belonging to the lower group is the other element When the signal is input to the power supply circuit, the voltage level of the signal is changed by the level shift circuit. The power supply circuit according to claim 1 or 2,
An AC couple is inserted between an element belonging to the upper group and an element belonging to the lower group, and a signal output from one element of the element belonging to the upper group and the element belonging to the lower group is transferred to the other element. A power supply circuit characterized in that, when inputting, the voltage level of the signal is changed by the AC couple. The power supply circuit according to claim 1 or 2,
An element belonging to the upper group and an element belonging to the lower group are elements that operate with different driving voltages. The power supply circuit according to claim 1,
Dividing the plurality of elements into the upper group and the lower group so that the total current consumption of the elements belonging to the lower group is greater than the total current consumption of the elements belonging to the upper group. A power circuit characterized by.   An optical disc apparatus comprising the power supply circuit according to claim 1.

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