JP4289064B2 - Portable audio equipment - Google Patents

Description

  The present invention relates to a portable audio device using a battery as a drive source, and more particularly to a startup control means thereof.

  In general, portable audio devices such as portable MD players and portable cassette players use one battery (charged battery or dry battery) having a voltage of about 1.2 V as a drive source, and boost the battery voltage to about 2 to 3 times. A DC-DC converter, a microcomputer driven by an output boosted by the DC-DC converter, and other circuits such as a signal processing LSI are provided.

  In the above portable audio device, low power consumption of each circuit is promoted to reduce battery consumption during operation and drive for a long time, while minimizing wasteful battery consumption during standby when not in use. It becomes important.

  In this regard, many conventional portable audio devices keep the battery voltage applied to the DC-DC converter in a driving state even during standby, and supply the boosted output to a microcomputer and other circuits. When the user performs any one of a number of operations that satisfy the conditions for starting the portable audio device, stop the clock oscillation of the microcomputer. A starting means for starting clock oscillation of the microcomputer and putting it into an operating state has been taken.

  Since the DC-DC converter, which is a booster circuit, is in an operating state and the boosted output is supplied to and driven by other circuits even during standby, this startup means is driven by a microcomputer clock. Although the oscillation is stopped, the battery consumption during standby is large, and if you leave the battery in the device for a while, the power will be consumed, causing the inconvenience that you will not be able to use it immediately when you want to use it. is there.

Therefore, recently, as shown in the block circuit diagram showing the circuit configuration relating to the startup control in the portable audio device of FIG. 3 and the timing chart of FIG. 4, the microcomputer 2 and the signal processing LSI 3 and other not shown in the standby state are shown. The DC-DC converter 1 is also brought into a non-driving state so that no load current flows through the circuit, and the power supply switch 4 for supplying the boosted output (power supply voltage V _DD ) to other circuits is turned off. Some measures are taken to give it a function to keep it.

In the case of the portable audio apparatus, naturally, the microcomputer 2, the signal processing LSI 3 and other circuits driven by the power supply voltage V _DD boosted by the DC-DC converter 1 are also stopped without being supplied with the power supply voltage V _DD. Therefore, power consumption during standby is suppressed as much as possible.

In order to start the portable audio device from standby, by executing one of a plurality of operations (for example, three operations) satisfying the start start condition such as pressing the PLAY button by the user, Any one of the switches SW1, SW2, or SW3 corresponding to the plurality of operations is turned on to enable the DC-DC converter 1 to be in a driving state and to output an enable signal CE for turning on the power supply switch 4. The latch circuit 5 (only this circuit is in an operating state by direct battery driving even during standby, but since the circuit does not have a clock, the current consumption can be suppressed to the extent that the battery consumption is hardly affected.) Is detected, and the DC-DC converter 1 is driven by the enable signal CE, and the boosted output is output. A source voltage V _DD is supplied through the power supply switch 4 to other circuits, whereby the microcomputer 2, the signal processing LSI3 and become other circuit operating conditions, whether is started triggered by the microcomputer 2 which operation the It is determined whether IN1 or IN2 or IN3 of the interrupt input corresponding to the operation is low, and the operation control corresponding to the result is performed in accordance with a processing procedure of a program recorded in a memory device (not shown) in advance. An activation control means is provided.

  The operations that satisfy the above-mentioned start start conditions are (a) key input operation of the PLAY button of the main body, (b) key input operation of the PLAY button of the remote control, (c) operation of attaching the main body to the charger, D) An operation in which a recording medium such as an MD is set in the apparatus main body and the lid or door of the apparatus is closed is applicable.

  For publicly known technical documents related to low power consumption and activation control of portable electronic devices such as portable audio devices according to the present invention, refer to “Portable electronic devices and control signal processing thereof” described in [Patent Document 1] below. This known technique is intended for portable personal computers and the like, and relates to a technique for reliably functioning low power consumption means for reducing the clock frequency entering the CPU by a key input waiting signal. It is not directly related to the start-up control of the portable audio device and is not compatible with the portable audio device.

Japanese Patent Laid-Open No. 7-141297

In the portable audio device of the block circuit shown in FIG. 3, when means for reducing the power consumption during standby by applying the DC-DC converter 1 to the non-driving state during standby is applied to the timing chart of FIG. As shown, when one of the operations satisfying the activation start condition (for example, the operation of pressing the PLAY button SW1 by the user for T1 time) is executed, the LATCH IN signal is input to the latch circuit 5, and the output signal LATCH OUT is output. (= Enable signal CE) is output, the DC-DC converter 1 is driven, and the boosted output (the power supply voltage V _{DD at} point B) is supplied to each circuit through the power supply switch 4, and the CPU RST signal is L The microcomputer 2 starts to oscillate the clock (almost so far). Then, after waiting for the time T2 when the clock oscillation is stabilized, the on / off states of the switches SW1, SW2, SW3, etc. corresponding to the activation input of the operation satisfying the activation start condition are examined.

  For this reason, there is a time difference from when the operation that satisfies the activation start condition by the user is started until the microcomputer 2 determines the executed operation. If this time difference is large, for example, the microcomputer 2 may check the state after the user performs a key input operation of the PLAY button on the main body and releases the button (see FIG. 4). As a result, it becomes impossible for the microcomputer to determine whether the activation has started, and the user's desired operation cannot be performed. Conversely, if the waiting time T2 is shortened and the start input is examined while the clock oscillation is not completely stabilized, an uncertain determination is made.

  The present invention has been made in view of the problem of start control that occurs when the means for reducing the power consumption during standby used in the portable audio device is used as much as possible. Accurate start control of the portable audio device is provided. It is intended to provide a novel activation control means capable of performing the above.

In order to achieve the above object, the present invention includes at least a DC-DC converter 1 using a battery BAT as a drive source and a microcomputer 2 driven by the boosted output V _DD of the DC-DC converter 1. In the portable audio device provided, when the portable audio device is in a standby state, a battery voltage is constantly applied and is in an operating state, and one of a plurality of operations that satisfy a start-up condition of the portable audio device is executed Further, the portable audio apparatus is activated by turning on the power supply switch 4 for bringing the DC-DC converter 1 in the non-driving state into a driving state and supplying the boosted output _VDD to other circuits for activation. A start-up input detection circuit 5 having a latch circuit for outputting a start enable signal CE; and the DC-D A latch circuit that is driven by the boosted output V _DD of the C converter 1 and that corresponds to the execution of a plurality of operations that satisfy the start-up conditions, and that holds the output until after the clock oscillation operation of the microcomputer is stabilized The microcomputer 2 includes a plurality of activation factor determination circuits 6, and each of the latch circuits of the activation factor determination circuit 6 after the microcomputer 2 has stabilized the clock oscillation in the microcomputer 2 after starting the portable audio device. The portable audio apparatus is characterized by comprising activation control means for determining an operation satisfying the executed activation start condition from the output and performing operation control corresponding to the operation.

  The portable audio device according to the present invention reduces the power consumption of the battery during standby by setting the DC-DC converter in a non-driven state during standby, and latches the activation factor immediately after the activation is started by the activation factor determination circuit. Among the multiple operations that satisfy the start start conditions, the operation (start factor) executed by the user can be determined by examining the latch output of the start factor determination circuit after the microcomputer stabilizes the clock oscillation. realizable.

  The best mode of a portable audio device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a block circuit diagram showing a circuit configuration relating to activation control in the portable audio apparatus of the present invention, and FIG. 2 is a timing chart at the start of activation.

As shown in FIG. 1, the portable audio apparatus of the present invention includes a DC-DC converter 1 using a battery BAT as a drive source, and a microcomputer 2 driven by the boosted output V _DD of the DC-DC converter 1. And a signal processing LSI 3, etc., and a plurality of operations satisfying the start-up condition of the portable audio device when the battery voltage (about 1.2 V) of the battery BAT is constantly applied during standby and in an operating state. When one of them is executed, the DC-DC converter 1 in a non-driven state is set in a driving state, and its boosted output V _DD (about 2.5 V) is supplied to another circuit to be activated. Start-up input detection circuit having a latch circuit for turning on the power supply switch 4 and outputting an enable signal CE for starting the start-up of the portable audio device When the by-on of the DC-DC converter 1 respectively switch correspond with driven by boosted output V _DD to execution of the activation start condition is satisfied multiple operations are turned on SW1, SW2, SW3 The microcomputer 2 includes an activation factor determination circuit 6 having a plurality of latch circuits that are held (latched) until the clock oscillation operation is stabilized in the microcomputer 2.

  The microcomputer 2 satisfies the activation start condition executed by the user from the output of each latch circuit of the activation factor determination circuit 6 after the clock oscillation in the microcomputer 2 is stabilized after the activation of the portable audio device is started. An activation control means is provided for determining which operation is performed and performing operation control corresponding to the operation by executing a program written in advance in a memory device such as a ROM (not shown). Once it is determined correctly after the clock oscillation is stabilized on the microcomputer 2 side that the user has executed an operation that satisfies the start start condition, normal operation control corresponding to the operation is performed thereafter.

As shown in the timing chart at the start of startup in FIG. 2, for example, a startup input for executing one of a plurality of operations satisfying the startup start condition such as pressing the PLAY button by the user (LATCH IN by turning on SW1) (L signal input) is input to the activation input detection circuit 5, the enable signal CE for activating the DC-DC converter 1 is output (LATCH OUT changes from L to H), and the DC-DC converter 1 at point B is output. To supply an output (power supply voltage V _DD ) boosted from about the battery voltage to about 2.5 V to drive the microcomputer 2 and other circuits, and also bring the activation factor determination circuit 6 into an operating state. When the voltage exceeds the set value, the CPU reset signal CPU RST changes from L to H and the microcomputer starts clock oscillation. Even before the clock oscillation stabilizes, before the user releases the PLAY button (during T1), the activation input is input to the latch circuit of the activation factor determination circuit 6 and the output is latched. Yes. The timing up to this point is almost the same, so that the microcomputer 2 checks which activation input is latched after the waiting time T2 when the clock oscillation is stabilized by the activation factor determination circuit 6 to determine the activation factor. It is possible to reliably perform the corresponding operation.

  As a result, since the microcomputer 2 can correctly determine the activation factor without worrying about the time T2 from one operation that satisfies the activation start condition of the user until the input is examined, the microcomputer 2 cannot perform the operation desired by the user. Can be prevented from occurring.

FIG. 3 is a block circuit diagram illustrating a circuit configuration relating to activation control in the portable audio device of the present invention. It is a timing chart at the time of start-up of the circuit. It is a block circuit diagram showing the circuit structure which concerns on starting control in the conventional portable audio apparatus. It is a timing chart at the time of start-up of the conventional circuit.

Explanation of symbols

1 DC-DC converter 2 Microcomputer 3 Signal processing LSI
4 Power supply switch 5 Startup input detection circuit (latch circuit)
6 Activation factor determination circuit SW1, SW2, SW3 Switch corresponding to the operation satisfying the activation start condition BAT Battery V _DD Boosted output (power supply voltage)
T1 Time until the user presses and releases the PLAY button T2 Waiting time until the microcomputer stabilizes after starting clock oscillation

Claims (1)

In a portable audio device comprising at least a DC-DC converter using a battery as a drive source and a microcomputer driven by a boosted output of the DC-DC converter,
When the portable audio device is in a standby state, a battery voltage is constantly applied and the battery is in an operating state, and when one of a plurality of operations that satisfy a start-up condition of the portable audio device is executed, the non-driven state An activation input detection circuit having a latch circuit that outputs an enable signal for turning on a power supply switch for bringing the DC-DC converter into a driving state and supplying the boosted output to another circuit for activation;
A latch circuit that is driven by the boosted output of the DC-DC converter, and that corresponds to execution of a plurality of operations that satisfy the start-up condition, and that holds the output until after the clock oscillation operation of the microcomputer is stabilized An activation factor determination circuit having a plurality of
The microcomputer determines an operation satisfying the executed start start condition from the output of each latch circuit of the start factor determination circuit after the clock oscillation in the microcomputer after the start of the start of the portable audio device is stabilized. And a start-up control means for performing operation control corresponding to the operation.

Images