JPS62127915A - Electronic equipment - Google Patents

Abstract

PURPOSE:To form an electronic equipment with a low power consumption and a very long battery life by supplying an electric power source to a printing means from an oscillating control system power source circuit when a battery voltage comes to be a prescribed voltage or below. CONSTITUTION:A power source part 10 is composed of a battery 11, a power source switch 12, a constant voltage circuit 13 which is a serial control system power source, a DC-DC converter A14 to supply a driving power source Vm to a printer motor driving circuit 40, a CPU 20, a memory 30, etc. The constant voltage circuit 13, when the power source switch 12 is turned off, supplies a memory back-up power source Vd to the memory 30, and supplies the driving power source Vd to the printer motor driving circuit 40 when the power source switch 12 is turned on. When the battery voltage comes to be the prescribed voltage or below, by supplying the power source to the printing means from an oscillating control system power source, the electric equipment with the low power consumption and the very long battery life can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a battery-driven electronic device that includes a printing unit that prints out information and a storage unit that stores processing information.

[Prior Art] In conventional devices of this kind, when the power switch is turned on, the voltage from the battery is converted to a constant voltage by a DC-DC converter, which is an oscillation-controlled constant voltage circuit, and the voltage is used to drive the motor of a printer, for example. It was used as a power source for printers and printer print heads. Therefore, even if the battery power supply voltage drops, the output voltage from the DC-DC converter is kept constant, and the range of usable battery power supply voltages is widened, resulting in a longer battery life.

[Problems to be Solved by the Invention] However, the efficiency of the DC-DC converter is lower than that of a series controlled constant voltage circuit, and a certain amount of loss is unavoidable.

[Means for Solving the Problem] The present invention has been made in view of the above-mentioned problem, and as a means for solving this problem, for example, in this embodiment, the storage contents of the storage means are retained when the power switch is turned off. a first series-controlled power supply circuit for supplying power; a detection means for detecting battery output voltage when the power switch is turned on; and a second series control power supply circuit for supplying power to drive the printing means when the detection means detects a predetermined voltage or higher.
and an oscillation-controlled power supply circuit that supplies power to drive the printing means when the detection means detects a voltage below a predetermined voltage.

[Function] In this configuration, when the battery pressure is higher than a certain voltage when the power switch is turned on, and if power can be supplied from the series-controlled power supply circuit to the printing means, the efficient series-controlled power supply circuit supplies power to the printing means. By supplying power to the printing means from the oscillation-controlled power supply circuit when the battery voltage falls below a predetermined voltage, it is possible to provide an electronic device with low power consumption and a very long battery life.

[Example] Hereinafter, an example according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment according to the present invention, in which reference numeral 10 indicates a power supply unit, and 20 indicates a C control unit that controls the entire embodiment.
PU, 30 is a memory, 40 is a printer motor drive circuit,
45 is a printer head, 50 is a keyboard, and 60 is a display device.

The power supply unit 10 of this embodiment has the following configuration.

That is, a battery 11, a power switch 12, a constant voltage circuit 13 which is a series controlled power supply circuit, and a printer motor drive circuit 40.
DC-DC converter A14 that supplies drive power Vm to
, CPU20. It is composed of a DC-DC converter B15 that supplies digital circuit power to the memory 30 and the like. The constant voltage circuit 13 controls the memory 3 when the power switch 12 is off.
A memory backup power supply Vd is supplied to the printer motor drive circuit 40 when the power switch 12 is turned on.

A detailed circuit of this power supply section 10 is shown in FIG.

The specific operation of the power supply section 10 will be explained below with reference to FIG. 2.

When the power switch 12 is "off", no voltage is supplied to the base of the transistor (hereinafter omitted) TR2, and this TR
2 is in the "on" state. Therefore, the output a of the constant voltage IC 13a is applied to the base of the TRI, and the TRI is turned on.

On the other hand, since TR3 is “off”, diode D
2 is "°° off", and a voltage determined by the TRI's output voltage VREG and the voltage division ratio of the resistor R4+-R5 is applied to the constant voltage IC 13a, and the constant voltage IC 13a outputs an output so that the TRI output voltage is constant. a and supplies a constant voltage Vd to the memory 30.

When the power switch 12 is turned on in this state, the TR
The battery voltage of battery 11 is applied to the base of TR2, and TR2
The base of is reverse biased and TR2 is turned "off".

Therefore, the output a of the constant voltage IC 13a is not applied to the base of the TRI, and the TRI is in an "off" state. Therefore, once the power switch 12 is turned on, the memory power Vd is no longer supplied via D3.

Thereafter, the circuit voltage will be supplied from the DC-DC converter B15.

Here, if the battery voltage is higher than the Zener voltage of Zener diode ZD1, ZDI turns "on" and TR
The base of transistor 6 becomes forward biased, turning TR6 "on." When TR6 is turned on, TR5 is turned off and the DC-DC converter A14 does not operate.

On the other hand, TR3 is an output transistor for converting the voltage of the battery 11 into a constant voltage and supplying it to the printer motor drive circuit 40, etc., and the base of this TR3 is a constant voltage IC1.
The output a of 3a is connected to achieve constant voltage.

When the power switch 11 is “on”, the constant voltage IC 13a
The human power b'α is changed to a voltage determined by the voltage division ratio of the TRI output voltage VREG supplied via Dl and the resistors R4 and R5, and the output voltage of TR3 supplied via D2 and the voltage determined by the resistors R7 and R8. A voltage value determined by the voltage division ratio is supplied, and the constant voltage IC 13a controls the output a so that the input voltage is constant, that is, the output voltage of TR3 is constant. The output voltage regulated in this manner is supplied to the printer power supply Vm to the printer motor control circuit 40 and the like via the diode D4.

Next, when the output voltage of the battery 11 decreases and becomes equal to or less than the Zener voltage of ZDI, ZDI enters the "off" state, and accordingly, the operation of the DC-DC converter A14 is started.

At this time, the battery voltage is supplied to the collector of TR4, and the voltage is also supplied to the base via the resistor 10.
TR4 is always in the "on" state.

First, the voltage that had been supplied to the base of TR6 via ZDl is no longer supplied, and TR6 becomes 'off'.

Therefore, TR5 turns on, and a current flows through the primary side of the transformer T1 of the DC-DC converter. This current change is transmitted to the secondary side of the transformer T1, and the current is transmitted to the secondary side via D5. An output voltage appears. This output voltage is fed back to the base of TR6 through Zener diode ZD2, turning TR6 "on". As a result, TR5 turns "off" and current flows through the primary side of transformer T1. No current flows, the output voltage decreases, and eventually TR6 turns "off"
TR5 turns "on" and the above operation is repeated again.

In this way, by alternately turning TR5 and TR6 on and off, a constant high-frequency voltage is output. This is output via DC and smoothed by smoothing capacitor C5 to obtain the desired output voltage. Get Vm.

Although this embodiment describes an example in which the battery voltage is detected using a Zener tie auto, the present invention is not limited to this, and the detection may be performed using a voltage comparator or the like.

[Effects of the Invention] As explained above, according to the present invention, when the battery voltage is higher than a predetermined voltage when the power switch is turned on, and if sufficient power supply voltage can be supplied to the printing means from the series-controlled power supply circuit, By supplying power to the printing means from an efficient series-controlled power supply circuit, and when the battery voltage falls below a predetermined voltage, the oscillation control power supply circuit supplies power to the printing means, resulting in low power consumption. It is possible to provide electronic devices with extremely long battery life.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment according to the present invention, and FIG. 2 is a detailed circuit diagram of a power supply section of the embodiment. In the figure, 10...power supply section, 11...battery, 12...power switch, 13...constant voltage circuit, 14.15...
DC-DC converter, 20...CPU, 30...
Memory, 40...Printer motor drive circuit, 45...
・It is a printer head.

Claims (2)

[Claims] (1) In a battery-powered electronic device equipped with a printing means for printing out information and a storage means for storing processing information,
a first series-controlled power supply circuit that supplies power to maintain the storage contents of the storage means when the power switch is turned off; a detection means that detects a battery output voltage when the power switch is turned on; and when the detection means detects a voltage equal to or higher than a predetermined voltage. The present invention is characterized by comprising a second series-controlled power supply circuit that supplies the printing means driving power, and an oscillation-controlled power supply circuit that supplies the printing means driving power when the detection means detects a predetermined voltage or less. Electronics. (2) The electronic device according to claim 1, wherein one circuit serves as both the first series-controlled power supply circuit and the second series-controlled power supply circuit.