JPH09181799A - Portable telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the portable telephone set in which noise by a charging circuit of a secondary battery is not caused during speech and a diversified charging power supply is used. SOLUTION: A charging circuit 14 of a pulse width modulation system charges a battery 15 with a current from an external power supply 3. A charging control circuit 13 obtains a speech state signal S3 from an equipment control section 17 during a speech to stop the operation of the charging circuit 14. When a plug 31 of an external power supply 3 is plugged in a jack switch 11, the charging control circuit 13 is set to the rapid charging mode to cause a large mean charging current Imr to the charging circuit 14. When the plug 31 of the external power supply 3 is plugged in a jack switch 12, the charging control circuit 13 is set to the low charging mode to cause a small mean charging current Ims to the charging circuit 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile phone equipped with a battery charging circuit.

[0002]

2. Description of the Related Art A conventional mobile phone of this type is shown in FIG.
This will be described with reference to the block diagram of FIG. Mobile phone 1 in FIG.
In A, the wireless unit 18 forms an interface circuit for wireless radio waves with a communication partner. The receiving circuit 19 and the transmitting circuit 20 form a voice interface circuit with the user.
The reception circuit 19 includes a receiver amplifier and a receiver, and the transmission circuit 20 includes a microphone amplifier and a microphone. Battery 15, which is a secondary battery such as a NiCd battery, produces a battery voltage Vb of about 4.8V. In this mobile phone 1A, the battery 15 is shown as being built in the main body, but the battery 15 may be mounted outside the main body. The DC / DC converter 16, which is a power supply circuit, converts the battery voltage Vb of the battery 15 into a predetermined voltage and supplies it to the device control unit 17, the wireless unit 18, the receiving circuit 19, and the transmitting circuit 20. DC / DC converter 1
6 is activated by turning on a power switch (not shown). The device control unit 17A includes a microprocessor circuit (C
PU) as a main constituent element, and controls a predetermined circuit among the above-mentioned circuits to perform outgoing / incoming call control, call control, and various operation controls. The charging circuit 21 charges the battery 15 with electric power from the external power supply 3. In addition, in FIG. 1, regarding the connection between the respective circuits, only the connection regarding the power supply is shown.

The plug 31 of the external power supply 3 is a mobile phone 1A
When it is inserted into the jack 22, the charging circuit 21 connected to the jack 22 charges the battery 15 regardless of whether the mobile phone 1A is talking or waiting. Therefore,
The DC / DC converter 16 is supplied with the electric power from the charging circuit 21 and the electric power from the battery 15 in a floating state. The charging circuit 21 uses pulse width modulation (P
It is a constant current supply circuit using the WM) method. In addition, the external power source 3 has an AC / AC for converting 240V AC to 9V DC.
AC adapter with built-in DC converter, DC / DC to convert DC12V from car battery to DC9V
Generally, battery voltage V, such as a power adapter with a built-in converter
A dedicated power supply with an output voltage slightly higher than b is used.

[0004]

In the above-mentioned conventional mobile phone, the pulse charging current generated by the charging circuit 21 is
During a call by being directly radiated to the telephone function unit including the device control unit 17A, the wireless unit 18, the receiving circuit 19 and the transmitting circuit 20, or leaking into the telephone function unit by conduction through the DC / DC converter 16. In the above, there was a case where pulse noise was generated in the voice generated by the receiving circuit 19 or the voice signal generated by the transmitting circuit 20 and the voice quality was impaired.

Further, since the external power source 3 requires a peak current capacity larger than the average charging current specified by the charging circuit 21, it is necessary to use a dedicated power source as the external power source 3, so that there is a large restriction in selection. It was

[0006]

A mobile phone according to the present invention comprises a radio section which forms an interface circuit for radio waves with a communication partner, a reception circuit and a transmission circuit which form a voice interface circuit with a user, and a battery. A secondary battery that generates a voltage, a power supply circuit that converts the battery voltage into a predetermined voltage and supplies the voltage to a predetermined circuit in the device, and pulse width modulation that receives power from an external power source to charge the secondary battery System charging circuit and a predetermined circuit inside the device are controlled to make and receive calls,
In a mobile phone having a device control unit that performs call control and various operation controls, charging that controls the charging circuit to stop charging of the secondary battery when a busy signal is received from the device control unit A control circuit is further provided.

In the portable telephone, the charging control circuit is
When it is detected that the signal during the call is not received and the power from the external power source is received by the first external power source terminal, the charging current of the charging circuit is set to the first current value. When it is detected that the signal from the external power supply is received at the second external power supply terminal, the charging current of the charging circuit is set to A configuration can be adopted in which the second current value lower than the first current value is set.

In the portable telephone, the external power source supplies electric power from a plug, and each of the first and second external power source terminals has a connection terminal for connection with the charging circuit by inserting the plug. The charging control circuit detects the switching of the switch and determines which of the first and second external power supply terminals is receiving power from the external power supply. It can be configured to make a judgment.

[0009]

Next, the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a mobile phone according to an embodiment of the present invention. Further, FIG. 2 is a waveform diagram of the output current Ic of the charging circuit 14 in the present embodiment.

This mobile phone 1 is the mobile phone 1 of FIG.
Battery 15, DC having the same structure, function and connection as A
The / DC converter 16, the wireless unit 18, the receiving circuit 19, and the transmitting circuit 20 are provided. Device control unit 1 of mobile phone 1
In addition to the function of the device control unit 17A of FIG. 4, 7 has a function of sending a busy signal S3 to the charging control circuit 13 when the mobile phone 1 is busy. While the mobile phone 1 is on standby, the device control unit 17 stops sending the busy signal S3. The PWM charging circuit 14 charges the battery 15 with electric power from the external power supply 3. However, the charging circuit 14 can set two types of charging currents for the battery 15, quick charging and low current charging, by controlling the switch signal S4 generated by the charging control circuit 13, and the charging of the battery 15 is turned on.・ Turned off.

The operation of charging the battery 15 will be described in detail below. The jack switch 11 is an external power supply terminal for quick charging, and the jack switch 12 is an external power supply terminal for low current charging. The rapid charge is, for example, a case where the battery 15 is charged with an average current of 350 mA, and the low current charge is, for example, a case where the battery 15 is charged with an average current of 100 mA. For example, the peak current capacity of the external power supply 3 is 700
If it is about mA, the plug 31 which is a power supply terminal of the external power supply 3 is inserted into the jack switch 11, and if the peak current capacity is about 200 mA, the plug 31 is inserted into the jack switch 12. Jack switches 11 and 12
Also, when the plug 31 is inserted, the input terminal is switched to connect the plug 31 to the common terminal. These common terminals are connected to the resistor Ra which is the power input terminal of the charging circuit 14 for quick charging in the case of the jack switch 11 and the power input terminal of the charging circuit 14 for low current charging in the case of the jack switch 12. It is connected to a resistor Rb. The terminals of the jack switches 11 and 12 that are connected to the plug 31 are connected to the charging control circuit 13, and when the plug 31 is inserted, the jack switch 11 is connected to the plug 31.
Insertion detection signal S1, that is, output voltage Ve of external power supply 3
To the charging control circuit 13 and the jack switch 12 sends to the charging control circuit 13 a detection signal S2 for inserting the plug 31.

The charging circuit 14 uses the current I from the external power source 3.
A current limiting circuit that limits c, a switch circuit that switches the current Ic, and a switch width control circuit that controls the switch width W of the current Ic that passes through the switch circuit according to the switch signal S4 from the charge control circuit 13. The charging circuit 14 sets the peak charging current Id to a first current value, for example, 700 mA when receiving power from the jack switch 11, and sets the peak charging current Id to first current when receiving power from the jack switch 12. A second current value lower than the value, for example, 200 mA is set. However, during the call of the mobile phone 1, the charging control circuit 13 does not generate the switch signal S4 because it receives the call signal S3, and the switch circuit blocks the passage of the current Ic, so that the charging circuit 14 charges. No current Id is generated. That is, the charging circuit 14 does not charge the battery 15 during a call of the mobile phone 1. Therefore, during a call, circuits related to the call, such as the receiving circuit 19 and the transmitting circuit 20, do not receive the pulse noise generated by the charging circuit 14,
The call quality of the mobile phone 1 can be kept good.

On the other hand, when the portable telephone 1 is on standby, the charging control circuit 13 does not receive the busy signal S3, so that the switch signal S4 having the cycle T and the switch width W is generated. When the charging control circuit 13 detects that the jack switch 11 receives the power from the external power source 3 by receiving the detection signal S1, the charging control circuit 13 outputs the average charging current Im to the battery 15 to the first current value Imr, for example, 350 mA. Set to. That is, the charge control circuit 13 uses Imr = Id · Wr / T, that is, Wr.
/T=0.5 duty cycle switch signal S
4 is sent to the charging circuit 14. The average charging current Imr can be changed by setting this duty appropriately.
The charging circuit 14 rapidly charges the battery 15 with the current Ic having the same waveform as the received switch signal S4.

The charge control circuit 13 also detects the detection signal S2.
By detecting that the power from the external power source 3 is received by the jack switch 12, the average charging current Im to the battery 15 is set to the second current value Ims, for example, 100.
Set to mA. That is, the charging control circuit 13 sets Ims = I
The switch signal S4 having a duty such that d · Ws / T, that is, Ws / T = 0.5, is sent to the charging circuit 14. The charging circuit 14 charges the battery 15 at a low current with the current Ic having the same waveform as the received switch signal S4. As described above, since the mobile phone 1 has the two modes of quick charging and low current charging, there is an effect that the battery 15 can be charged using various external power sources 3.

Explaining the charging circuit 13 in detail, the resistors Ra and Ra constitute a current limiting circuit, and the resistor R
1, the diode D1 and the FET transistor Q1 form a switch circuit, and the resistors R2 and R3 and the NPN transistor Q2 form a switch width control circuit. The switching circuit is connected between the common terminal of the jack switch 11 and the anode of the backflow prevention diode D1 via the resistor Ra, and between the common terminal of the jack switch 12 and the anode of the diode D1 via the resistor Rb. Connect to. The cathode of the diode D1 and the drain of the transistor Q1 are connected to each other, and the drain and the gate of the transistor Q1 are connected to each other, and the source of the transistor Q1 is connected to the charging circuit 1.
4 charging current output terminal. The resistor R1 is connected between the gate and drain of the transistor Q1.

In the switching width control circuit of the charging circuit 14, the base of the transistor Q2 receives the switching signal S4 via the resistor R2. The collector of the transistor Q2 is connected to the gate of the transistor Q1 and the emitter is connected to the ground potential. Resistor R3 is transistor Q
2 is connected between the base and the emitter. Now, when a positive level switching signal S4 is applied to the resistor R2, the transistor Q2 turns on and the transistor Q1
The gate of turns to the on level. As a result, the transistor Q1 is turned on to generate the charging current Ic (Id).

When the output voltage of the external power supply 3 is Ve, the ON voltage of the diode D1 is Vd, the ON voltage of the transistor Q1 is Vq, and the voltage of the battery 15 is Vb, the resistance value of the resistor Ra is RA. , Average charging current Imr = {(Ve−Vq−Vb) · Wr} / (T
・ RA) Further, when the resistance value of the resistor Rb is RB, the average charging current Ims = {(V
e-Vq-Vb) .Ws / (T.RB). Therefore, the resistors RA and RB of the resistors Ra and Rb are
The battery voltage Vb of the battery 15 is a fixed value of about 4.8V,
If it is determined that the external power supply 3 has a voltage Ve of about 9 V, it can be determined according to the value of the average charging current Im.

FIG. 3 is a flowchart of the charging operation of the battery 15 in this embodiment. Hereinafter, the charging operation of the battery 15 in the mobile phone 1 will be described with reference to FIGS. 1 and 3.

When the plug 31 of the external power source 3 is inserted into the jack switch, for example, the jack switch 11, and the external power source 3 is activated with the power switch of the mobile phone 1 being turned on, the charging control circuit 13 is operated from the jack switch 11. The detection signal S1 for rapid charging is received (step 1). At this time, the device control unit 17 determines whether the mobile phone 1 is in a call, that is, whether the wireless unit 18 is in the state of transmitting radio waves from the wireless unit 18 or is in a standby state. The circuit 13 receives the busy signal S3 from the device controller 17 (step 2). When the charge control circuit 13 receives the call signal S3 (Y in step 2), the charge control circuit 13 stops transmitting the switch signal S4, and the battery 1
The charging of 5 is stopped (step 4). Step 2
When the charging control circuit 13 does not receive the busy signal S3 (N in step 2), the charging control circuit 13 sends the switch signal S4 to cause the charging circuit 14 to charge the battery 1
Charging to 5 is started (step 3). After this, when the call state is entered (Y in step 2), the flow is step 4
Then, charging of the battery 15 is stopped.

In this embodiment, the value of the charging current Im is set to Imr for quick charging and Ims for low current charging.
The number of these charging currents Im is increased by increasing the number of jack switches and charging current Ic.
It is needless to say that it is possible to use more than two types by using a technique similar to that of the present embodiment, such as providing a large number of limit values.

[0022]

As described above, according to the present invention, the charging control circuit controls the charging circuit of the PWM system to stop the charging of the secondary battery during a call of the mobile phone. The circuit does not generate pulse noise, and there is an effect that voice quality with little noise and high intelligibility can be obtained.

Further, according to the present invention, since the charging control circuit and the charging circuit are provided with a mode for charging the secondary battery at a low current and a mode for rapidly charging at a large current, various power sources for the charging current can be used. There is an effect that a different power supply can be used.

[Brief description of the drawings]

FIG. 1 is a block diagram of a mobile phone according to an embodiment of the present invention.

FIG. 2 is a waveform diagram of the output current Ic of the charging circuit 14 in the present embodiment.

FIG. 3 is a flowchart of a charging operation for battery 15 in the present embodiment.

FIG. 4 is a block diagram of a mobile phone according to the related art.

[Explanation of symbols]

 1 Mobile Phone 3 External Power Supply 11, 12 Jack Switch 13 Charging Control Device 14 Charging Circuit 15 Battery 16 DC / DC Converter 17 Device Control Section 18 Radio Section 19 Receiver Circuit 20 Transmitting Circuit 31 Plug D1 Diode Q1, Q2 Transistors R1 to R3 , Ra, Rb resistors

Claims (3)

[Claims] 1. A radio unit forming an interface circuit for radio waves with a communication partner, a receiver circuit and a transmitter circuit forming a voice interface circuit with a user, a secondary battery generating a battery voltage, and the battery voltage. To a predetermined voltage and supply it to a predetermined circuit in the device, a pulse width modulation type charging circuit that receives power from an external power source to charge the secondary battery, and a predetermined circuit in the device. In a mobile phone including a device control unit that controls a circuit to perform outgoing / incoming call control, call control, and various kinds of operation control, the charging circuit is controlled to control the charging circuit when a busy signal is received from the device control unit. A mobile phone further comprising a charge control circuit for stopping charging of the secondary battery. 2. The charging control circuit is not receiving the busy signal, and the power from the external power supply is supplied to the first power supply.
When it is detected that the external power supply terminal is receiving, the charging current of the charging circuit is set to a first current value,
When it is detected that the second external power supply terminal is receiving the power from the external power supply, the charging current of the charging circuit is not received. The mobile phone according to claim 1, wherein the second current value is lower than the second current value. 3. The external power source supplies power from a plug, and each of the first and second external power source terminals switches and connects a connection terminal to the charging circuit to the plug by inserting the plug. The charging control circuit detects the switching of the switch and determines which of the first and second external power supply terminals is receiving power from the external power supply. The mobile phone according to claim 2, wherein