JPH08242544A - Power source circuit for portable terminal - Google Patents

Abstract

PURPOSE: To reduce the power consumption of a terminal by cutting off the feedback of a ripple noise component when the current consumption of the terminal is small by providing a switching element to the ripple noise component feedback circuit of a switching regulator. CONSTITUTION: A terminal is mounted with a regulator 18 which is operated by the electric power from a battery and controls an FET1 based on the output of a comparator COMP. At the time of controlling the FET1, a power-supply voltage VCC2 which contains a lowered ripple voltage is obtained from a power- supply voltage VCC1 by connecting a coil L2 and capacitor C3 after a capacitor C2. Since the DC component of the output voltage is fed back from the voltage VCC2, only the ripple component in the voltage VCC1 containing a high ripple voltage is fed back through a capacitor C5. However, the power consumption of the regulator 18 becomes larger when a CPU stops operations and a circuit current becomes extremely small. Therefore, the CPU reduces the current consumption of the terminal equipment without feeding back ripples by turning off the FET2 by raising the level of a feedback control signal S1 to an 'H' level.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low power consumption portable terminal device (hereinafter referred to as a handy terminal) which is operated by a battery.
Of the power supply circuit and the power supply control sequence.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram of an existing handy terminal. CPU2, ROM3, RAM5, LCD
The controller 4, the system controller 7, the RTC (real time clock = clock function) 9, and the I / O controller 8 are connected by a control line by a data bus and an address bus, and the display device 15 such as a liquid crystal panel is connected to the LCD controller 4. Has been done. In this example, the system controller 7, RTC 9, and I / O controller 8
Is partially incorporated in the gate array 6.

The system controller 7 is always CP
The state of U2 is monitored, and after the processing of the CPU2 is completed, the data bus is released and the CPU clock X1 is stopped. When an interrupt factor is generated by a timer or an external signal, interrupt the CPU2,
The oscillation of the CPU clock X1 is started again. I / O
Controller 8 is key switch 10, buzzer 11, EL
Along with the (electronic luminescence) 14 and the like, a communication coil 13 and a wireless block 12 which constitute a communication function unit.
Are in control.

The power supply circuit 1 is connected to the system controller 7 and not only supplies power to each circuit, but also constantly supplies a control signal to the system controller 7 to monitor the battery state and perform an optimum operation as a handy terminal. to be sending. The gate array 6 is always operated by the gate array clock X2.

FIG. 8 is a circuit diagram showing in detail a conventional power supply circuit. The power source in this example uses two main batteries 16 and a secondary battery 17 for memory backup. As a main battery, three NiCd storage batteries are connected in series to each other.
It has a voltage of 6V. 24 and 25 are series regulators, which are particularly suitable for a handy terminal equipped with a radio because of the reason that the number of parts is smaller than that of a switching regulator and there is no ripple.

Circuit power supplies are VCC1, VCC2, and VCC3.
There are four types, namely, VIN and VIN, a voltage of 3V is applied to VCC1 to VCC3, and a voltage of 3.6V of the main battery 16 is applied to VIN as it is. VC
If the main battery 16 has a normal voltage value, the voltage C1 is always applied with a voltage limited to the upper limit of 3 V by the main battery. The VCC3 is a power source for a normal digital circuit, and is backed up by the secondary battery 17 even when the voltage of the main battery 16 drops. Further, the wireless block 12 shown in FIG. 9 is separated from the series regulator 24 in order to reduce voltage fluctuation and digital noise, and obtains power from VCC2.

The voltage determination circuit is a BLD having a determination voltage of 3.0V.
Two circuits, M and BLDH having a judgment voltage of 3.4V are provided. If the voltage of the main battery 16 is 3.4V or less, BL is set.
The DH output S6 becomes "L" and a warning for battery replacement is output to the display device, and the voltage of the main battery 16 is 3.0 V.
When it drops below, the BLDM output S7 becomes "L", and the operation of the handy terminal is stopped by the control of the system controller 7, and at the same time the transistor TR2 is turned off. In this state, current flows from the secondary battery 17 to VCC3 via the diode D3,
The circuit connected to CC3 will be backed up. On the other hand, since the transistor TR2 is off, the secondary battery 17 is connected to the circuit power supply VCC1 and the main battery 1
6. The sneak of current to the circuit power supply VIN is prevented.

When the secondary battery 17 is not charged, the secondary battery 17 is charged from the main battery 16 through the resistor R9. At this time, if the voltage of the secondary battery 17 is lower than the voltage of the main battery 16 even if the main battery 16 is 3 V or less and the transistor TR2 is turned off, the diode D4
The circuit power supply VCC3 current is supplied from the main battery 16 via the above, and the secondary battery 17 is charged to the same potential as the main battery 16.

When the voltage of the main battery 16 exceeds 3.4 V due to battery replacement or the like, the BLDH output S6 changes from "L" to "H", and the NMI signal S5 has a constant width at the rising edge. Is output, and the system controller 7 applies NMI (non-maskable interrupt = interrupt that cannot be disabled by software) to the CPU 2 by this pulse, the CPU performs NMI processing, and the operation before the main battery 16 drops The resume operation can be performed.

FIG. 9 is a block diagram showing a supply destination of each circuit power source in a conventional handy terminal, in which a lot of ripple noise is generated from a driving circuit during operation.
The EL 14 is directly connected to the circuit power supply VIN in view of the fact that a relatively large current flows.

The analog circuit 22 is supplied with power from the circuit power supply VCC1. The analog circuit 22 is not included in the analog portion of FIG. 2, that is, the temperature correction circuit for the negative power supply of the LCD controller 4, the filter for performing the data processing of the wireless block 12 and the communication coil 13, and the gate array 6 such as the waveform shaping circuit. A circuit of the / O controller 8 and the like are shown.

The circuit power supply VCC2 is the wireless block 1
2 is supplied. The circuit power supply VCC3 is backed up by the secondary battery 17 as described above, and C shown in FIG.
It is supplied to the digital circuit 23 such as the PU 2, the ROM 3, the RAM 3, a part of the LCD controller 4 and the gate array 6.

As described above, particularly in a wireless handy terminal, it is common to use a series regulator instead of a switching regulator as a power source. Further, when the main battery 16 is removed for a long time, the secondary battery 17 is discharged to the discharge end voltage (a characteristic of the secondary battery, which is a voltage that does not deteriorate even if charging and discharging are repeated) or less. I will proceed. This is called "deep discharge" or "over discharge".

Further, an NMI signal is applied to the CPU 2 in order to resume when the battery is replaced. However, since the CPU 2, the RAM 5, etc. are always backed up by the secondary battery 17, it is difficult to control the power-on reset, and the automatic reset is performed. I couldn't.

[0015]

In a power supply circuit using a series regulator, although the circuit configuration and the like are simple, the power supply efficiency becomes poor when the power supply voltage is high, so that the capacity of the battery cannot be effectively used, There was a problem that the battery life would not be extended.

On the other hand, in a circuit using a switching regulator, it is difficult to eliminate the influence of ripple noise sneaking in. Regarding the consumption current, the effect is high during operation, but the consumption current is small when the CPU 2 is not operating. At times, the switching regulator itself consumes a large amount of current.

Further, the secondary battery used for memory backup has a problem that its life becomes short if deep discharge is repeated. If the power-on reset is not applied, the handy terminal may run away or the data may be corrupted when the primary battery is inserted for the first time, or when the battery is inserted with the memory contents not retained. There was an issue in question.

[0018]

According to the present invention, a switching regulator is used for a handy terminal in order to extend the battery life, and a choke coil for smoothing is provided to reduce the ripple voltage of the switching regulator. The circuit power supply is separated.

A switching regulator provided with a smoothing choke coil is a generally known circuit technology.
By controlling the feedback of the ripple from the output according to the operating current, the consumption current of the switching regulator itself when the operating current is small is reduced.

Regarding the secondary battery for memory backup, by monitoring the power supply voltage backed up from the secondary battery and disconnecting the secondary battery from the circuit when the backup voltage becomes a certain voltage or less. The discharge of the secondary battery is stopped halfway.

Further, since the battery is resumed after the replacement,
The NMI signal is applied to the CPU to perform processing. At this time, the voltage of the secondary battery for memory backup is monitored, and when the voltage of the secondary battery is below a certain voltage, the contents of the memory are retained. It is the one that is reset as if not.

[0022]

According to the present invention, a switching regulator can be used as a power source for a handy terminal without being affected by ripple noise, and as a result, battery life can be extended as compared with the case of using a series regulator. The effect is particularly great when the battery voltage is higher than the circuit voltage.

Further, since the step-up switching regulator can be used, the battery voltage can be set lower than the operating voltage, and the degree of freedom in selecting the battery type is widened. Further, since there is no charge / discharge deterioration of the secondary battery, there is no need for battery maintenance, and the structure can be simplified.

Furthermore, after the primary battery is inserted, either power-on reset or resume processing by an NMI signal is automatically performed, so that malfunctions during battery replacement can be prevented.

[0025]

【Example】

(Embodiment 1) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. The circuit block of the entire handy terminal is the same as that of Fig. 2.

FIG. 1 is a circuit diagram showing a power supply circuit according to an embodiment of the present invention. Field effect transistor FET in the drawing
The diode connected in parallel with 1, FET3, and FET4 is a parasitic diode. As a power source, a main battery 16 and a secondary battery 17 for memory backup are provided.

In this example, it is assumed that the main battery is formed by connecting three NiCd storage batteries in series or three or four dry batteries in series. Therefore, the voltage is set in the range of 3.6V to 4.5V. The circuit power supplies are classified into VCC1, VCC2, and VCC3, and all the voltage values are 3.0V. Reference numeral 18 is a switching regulator. The switching regulator 18 is a self-exciting step-down type and is suitable when the change in current is wide (50 mA to 10 μA) as compared with the separately-excited type.

First, the circuit of the switching regulator 18 will be described. The voltage of the reference power source 19 is the resistance R3,
It is divided by R4. The output voltage of the reference power source and the voltage divided by the R1 and R2 are compared by the comparator COMP, and the field effect transistor FET1 is controlled by the output from the comparator COMP. Here, a smoothing coil is used to obtain a power supply with less ripple.

The main switching parts are field effect transistor FET1, capacitor C1, diode D1, coil L1, capacitor C2 and comparator COMP1.
It is composed by. Further, since the power supply voltage VCC1 has a large ripple voltage, the coil L is placed after the capacitor C2.
2 and the capacitor C3 are connected to each other to obtain the power supply VCC2 having a reduced ripple voltage. Since it is a self-excited type, in order to continue oscillation, a capacitor C4 and a resistor R5 are connected to the inverting terminal of the comparator COMP1 for feedback. Since the direct current component of the output voltage is fed back from this VCC2, there is no voltage drop in the coil L2. However, since switching does not operate properly unless a certain ripple voltage is generated, VCC1 with a large ripple voltage is used.
Therefore, only the ripple component is fed back through the field effect transistor FET2 and the capacitor C5, and the switching regulator using the smoothing coil described above is known.

However, in the above-described known circuit, the switching regulator itself consumes a large amount of current when the circuit current becomes extremely small, for example, when the operation of the CPU 2 is stopped and a wait state for an external interrupt occurs. , The problem occurs when the circuit current is small.

Therefore, in such a case, the feedback control signal S
By setting 1 to "H", the field effect transistor FE
T2 is turned off and ripple feedback is not performed, and the current consumption as a whole is made smaller. Next, a case where a circuit other than the switching regulator is used will be described.

The voltage determination circuit uses the minimum backup voltage of the memory (2V in this case although it depends on the memory) and the discharge end voltage (2V in this case) of the secondary battery 17 to determine the determination voltage to 2V, and the determination voltage. Is the circuit power supply VC
Same as C3, BLDM of 3.0V and judgment voltage of 3.4V
There are three BLDHs.

The NMI generating circuit 20 is a flip-flop F.
It is composed of F1, a resistor R6, a capacitor R6, and an inverter Q1, and the NMI inhibition signal S4 is "L" in the initial state. Here, the voltage of the main battery 16 is 3.4.
When the voltage exceeds V and the BLDH output S6 rises, the resistance 6
And a one-shot pulse determined by the time constant of the capacitor 6 is output, and this pulse becomes the NMI signal S5. When the NMI processing is started, the NMI prohibiting signal S4 becomes "H", and when the main battery 16 fluctuates in the vicinity of 3V, the NMI is multiplexed.
It is prohibited to generate the signal S5. The NMI prohibiting signal S4 becomes "L" when the main battery 16 has a voltage of 3V or less of the voltage determination circuit BLDM.

The reset signal generating circuit 21 is composed of a flip-flop FF2, an AND gate Q2, an OR gate Q3, a resistor R7 and a capacitor C7. When the voltage of the main battery 16 is equal to or lower than the voltage of 2V of the voltage determining circuit BLDL, The flip-flop FF2 is reset by the BLDL output S8, and the AND gate Q2 is opened. In addition, the voltage of the main battery 16 rises to 3.4 V or more,
When the NMI signal S5 is generated, the reset signal S2 is output. The reset signal S2 is an OR gate Q3, a resistor R
7, the signal output time is longer than the NMI signal S5 due to the configuration of the capacitor C7. When the operation of the CPU 2 after the reset is completed, the initialization end signal S3 becomes "H", so that the reset signal S is generated even if the NMI signal S5 is generated next.
2 will not be output. Further, when the voltage of the main battery 16 decreases and the voltage of the initialization end signal S3 becomes 3.0 V or less, it becomes “L”. Further, the state in which the flip-flop FF2 is set is maintained until the circuit power supply VCC3 becomes 2 V or less and the output S8 of the voltage determination circuit BLDL becomes “L”.

Next, the operation due to the fluctuation of the battery voltage will be described with reference to FIG. FIG. 3 is a timing chart of the circuit shown in FIG. First, the operation when the main battery 16 is inserted when the secondary battery 17 is not charged will be described.

When the voltage of the main battery 16 is 3.0 V or less, the operation of the switching regulator 18 is stopped and the field effect transistor FET1 remains ON. On the other hand, although substantially the same voltage is applied to the circuit power supplies VCC1 and VCC2, since the field effect transistor FET3 is off, the circuit power supply VCC3 has the field effect transistor FET3.
A voltage lower than the forward voltage of the parasitic diode 3 is applied. From this state, the voltage gradually rises, and the circuit power supply VCC3 changes the determination voltage (2.0
V) or higher, the reset of the flip-flop FF2 is released.

Further, the voltage of the main battery 16 is increased to 3.0V.
When the above is reached, the operation of the switching regulator 18 is started, the field effect transistor FET3 is turned on, and the circuit power supply VCC3 becomes 3.0V. Further, the voltage of the main battery 16 rises to 3.4 V or more, and BLDH output S6
Rises, the NMI signal S5 and the reset signal S2 are output.

At this time, when the voltage of the main battery 16 once becomes 3.0 V or less and 2 V or more and again becomes 3.4 V or more before the initialization operation is completed, the reset operation is performed again. If the conversion operation is completed, the process shifts to NMI processing. Next, during operation, the voltage of the main battery 16 is 3.0.
The case where the voltage drops below V will be described.

When the voltage of the main battery 16 drops to 3.0 V or less, the operation of the switching regulator 18 is stopped and the field effect transistor FET1 remains in the ON state. In this state, the BLDM from the voltage determination circuit BLDM
The output S7 becomes "L", and as a result, the system controller 7 stops the CPU2, and then the CPU clock X1.
Stop oscillating. At this time, the field effect transistor FE
T3 is turned off, and the field effect transistor FET4,
Circuit power supply VC from secondary battery 17 via diode D2
A current is supplied to C3, and the backup state is entered. At this time, no current flows through the circuit power supplies VCC1 and VCC2.

When the main battery 16 is no longer needed and the secondary battery 17 is further discharged and the circuit power supply VCC3 becomes 2 V or less, the output of the voltage determination circuit BLDL becomes "L" and the field effect transistor FET4 is turned off. Becomes After that, the current from the secondary battery 17 does not flow and over-discharge of the secondary battery is prevented.

FIG. 4 is a block diagram showing a supply destination of each circuit power source. The circuit power supply VCC1 includes a ripple, and the circuit power supply VCC1 is supplied to a circuit that is not affected by the ripple or the EL11 and the buzzer 14 that generate a lot of noise components.

On the other hand, the ripple of the circuit power supply VCC2 is smaller than that of the circuit power supply VCC1 and is supplied to the analog circuit 22 and the wireless block 12. The circuit power supply VCC3 is backed up by the secondary battery 17, and the digital circuit 2
3 is supplied. The digital circuit 23 includes the gates shown in FIG.

FIG. 5 is a circuit diagram in which the power source portion of the wireless block 12 is extracted. The circuit power supply VCC2 is stabilized and supplied as a wireless common power supply. The common part is TCXO (temperature-compensated crystal oscillator), VCO (oscillator whose frequency changes with voltage) and P in the wireless block 12.
LL (comparator for detecting the frequency difference and phase difference of TCXO by dividing the frequency of VCO). Especially, since the power supply voltage fluctuation becomes a frequency fluctuation element, the circuit power supply VCC2 is further stabilized. Here, the control of the transistor TR1 is controlled by the operational amplifier OPAMP. The output voltage is 2.8 V, which is lower than the circuit power supply VCC2. By sharing the reference voltage with the reference voltage 19 of FIG.
Even if there are variations, the circuit power supply VCC2> the wireless common power supply is always established. As a result, the voltage difference between the circuit power supply VCC2 and the wireless common power supply can be reduced.

As a power source for the receiving section of the wireless block 12, the circuit power source VCC2 is opened and closed by the field effect transistor FET5. Similarly, the power supply of the transmission unit of the wireless block 12 opens and closes the circuit power supply VCC2 by the field effect transistor FET6. However, sudden circuit power VC at the start of transmission
Due to the load variation of C2 and the load variation on the wireless common portion, the wireless common power supply may vary, and the wireless transmission frequency may vary. To prevent this,
The gate of the field effect transistor FET6 is not directly driven at the same timing as the control signal TXBC, but feedback is applied from the output side via the resistor 7 through the capacitor C8 to make the rise gentle. Also, turn on the wireless transmission power quickly.
The diode D3 is necessary to prevent FF and not emit unnecessary radio waves.

FIG. 6 is an explanatory diagram showing the relationship between the control signal TXBC and the radio transmission power source. The wireless transmission power supply starts rising almost linearly from the rise of the control signal TXBC. The time ΔT is determined by the time constants of the resistor 7 and the capacitor 7. Conventionally, as shown in FIG. 7, a capacitor C8
Was inserted between the resistor R8 and the ground. At this time, a time Td is required until the FET is turned on due to the threshold voltage of the field effect transistor FET6, and the rise is inferior in linearity as compared with FIG. In this way, the present invention can suppress fluctuations in the power supply and circuit load and maintain a stable frequency.

(Embodiment 2) FIG. 10 shows the MN of the present invention.
FIG. 7 is a circuit diagram showing another embodiment of the I generation circuit 20. In this example, a reset generation circuit 21 is added for the sake of explanation.

Explaining the NMI generating circuit 20,
When the voltage of the main battery 16 rises to 3.4 V or more and the BLDH output S6 rises, a one-shot pulse determined by the time constant of the resistor 10 and the capacitor 9 is input to the AND gate Q4. The NMI signal S5 is output when the NMI inhibit signal S4 is "L" and the flip-flop FF2 is set by the initialization end signal S3.

When the NMI processing is started, the NMI prohibiting signal S4 becomes "H" and the AND gate Q4 is turned off, so that the NMI signal S5 is not generated in multiple.

[0049]

EFFECTS OF THE INVENTION From the above configuration, the present invention (1) separates the circuit power supply from VCC1 to VCC3 to use a switching regulator without being affected by ripple even in a wireless handy terminal.
As a result, the life of the battery can be extended. (2) By controlling the feedback of the switching regulator, the current of the entire circuit can be further reduced when the output current is small. (3) It is possible to extend the life of the secondary battery itself by constantly monitoring the voltage of the memory backup power supply and preventing over-discharge of the secondary battery when the secondary battery discharge end voltage is reached. , No need to replace batteries. (4) The voltage of the memory backup power supply is constantly monitored, and when the memory backup voltage is low, the NIM operation after battery insertion or battery replacement is prohibited and reset to perform power-on reset and prevent malfunction of the device. . (5) When the main battery is removed by the time the initialization operation is completed immediately after resetting, the malfunction can be prevented by prohibiting the NIM operation and resetting when the voltage is restored thereafter. (6) By linearly raising the wireless transmission power supply, fluctuations in the power supply and circuit load can be suppressed and a stable frequency can be maintained. And so on.

[Brief description of drawings]

FIG. 1 is a diagram showing a power supply circuit that is an embodiment of the present invention.

FIG. 2 is a block diagram of a handy terminal.

FIG. 3 is a timing chart of the circuit shown in FIG.

FIG. 4 is a diagram showing a supply destination of each circuit power source.

FIG. 5 is a diagram in which a power source portion of a wireless block 12 is extracted.

FIG. 6 is a control signal TX of the field effect transistor FET6.
It is the figure which showed the relationship between BC and wireless transmission power supply.

FIG. 7 is a switch of a conventional wireless transmission power supply.

FIG. 8 is a diagram showing in detail a conventional power supply circuit.

FIG. 9 is a diagram showing a supply destination of each circuit power source in a conventional handy terminal.

FIG. 10 is a diagram showing a reset generation circuit 21 and an MN of the present invention.
FIG. 9 is a diagram showing another embodiment of the I generation circuit 20.

[Explanation of symbols]

 1 Power Supply Circuit 2 CPU 3 ROM 4 LCD Controller 5 RAM 6 Gate Array 7 System Controller 8 I / O Controller 9 RTC (Real Time Clock = Clock Function) 10 Key Switch 11 Buzzer 12 Wireless Block 13 Transfer Coil 14 EL (Electronic Luminescence) ) 15 display (liquid crystal panel, etc.) 16 main battery 17 secondary battery 18 switching regulator 19 reference power supply 20 NMI generation frequency 21 reset generation circuit 22 analog circuit 23 digital circuit

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[Procedure amendment]

[Submission date] May 26, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

[Figure 6]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 10

[Correction method] Change

[Correction content]

[Figure 10]

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

The system controller 7 is always CP
The state of U2 is monitored, and after the processing of the CPU2 is completed, the data bus is released and the CPU clock X1 is stopped. When an interrupt factor is generated by a timer or an external signal, interrupt the CPU2,
The oscillation of the CPU clock X1 is started again. I / O
Controller 8 is key switch 10, buzzer 11, EL
With such (electroluminescence Ssensu) 14, and controls the communication coil 13 and the radio block 12 constituting the communication function unit.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

The voltage determination circuit is a BLD having a determination voltage of 3.0V.
Two circuits, M and BLDH having a judgment voltage of 3.4V are provided. If the voltage of the main battery 16 is 3.4V or less, BL is set.
The DH output S6 becomes "L" and a warning for battery replacement is output to the display device, and the voltage of the main battery 16 is 3.0 V.
When it drops below, the BLDM output S7 becomes "L", and the operation of the handy terminal is stopped by the control of the system controller 7, and at the same time the transistor TR2 is turned off. When this occurs, current flows to VCC3 through the diode D 2 is a secondary battery 17, the V
The circuit connected to CC3 will be backed up. On the other hand, since the transistor TR2 is off, the secondary battery 17 is connected to the circuit power supply VCC1 and the main battery 1
6. The sneak of current to the circuit power supply VIN is prevented.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

As described above, particularly in a wireless handy terminal, it is common to use a series regulator instead of a switching regulator as a power source. In addition, the main battery 16 is a long period of time
When they are removed from each other , the secondary battery 17 is discharged below the discharge end voltage (a characteristic of the secondary battery that does not cause deterioration even after repeated charging and discharging). This is called "deep discharge" or "over discharge".

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

Further, the secondary battery used for memory backup has a problem that its life becomes short if deep discharge is repeated. If the power-on reset is not applied, the handy terminal may run away or the data may be corrupted when the primary battery is inserted for the first time, or when the battery is inserted with the memory contents not retained. There was a problem such as.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

Embodiments (Embodiment 1) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The circuit block of the entire handy terminal is the same as in FIG.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0027

[Correction method] Change

[Correction content]

In this example, it is assumed that the main battery is formed by connecting three NiCd storage batteries in series or three or four dry batteries in series. Therefore, the voltage is set in the range of 3.6V to 6.0V . The circuit power supplies are classified into VCC1, VCC2, and VCC3, and all the voltage values are 3.0V. Reference numeral 18 is a switching regulator. The switching regulator 18 is a self-exciting step-down type and is suitable when the change in current is wide (50 mA to 10 μA) as compared with the separately-excited type.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

The main switching portion is composed of the field effect transistor FET1, the capacitor C1, the diode D1, the coil L1, the capacitor C2 and the comparator COMP . Further, since the power supply voltage VCC1 has a large ripple voltage, the coil L2 is placed after the capacitor C2.
And a capacitor C3 are connected to obtain a power supply VCC2 having a reduced ripple voltage. Since it is a self-excited type, in order to continue oscillation, the capacitor C4 and the resistor R5 are connected to the inverting terminal of the comparator COMP for feedback. Since the direct current component of the output voltage is fed back from this VCC2, there is no voltage drop in the coil L2. However, since the switching does not operate properly unless a certain ripple voltage is generated, only the ripple component is fed back from the large ripple voltage VCC1 through the field effect transistor FET2 and the capacitor C5. A switching regulator using is known.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

The NMI generating circuit 20 is a flip-flop F.
It is composed of F1, a resistor R6, a capacitor C6 , and an inverter Q1, and the NMI inhibit signal S4 is "L" in the initial state. Here, the voltage of the main battery 16 is 3.4.
When the voltage rises above V and the BLDH output S6 rises, the resistance R
6 and a one-shot pulse determined by the time constant of the capacitor C6 are output, and this pulse becomes the NMI signal S5. NM
When the I process is started, the NMI inhibition signal S4 is "H".
When the main battery 16 fluctuates around 3V, multiple N
The generation of the MI signal S5 is prohibited. The NMI prohibiting signal S4 becomes "L" when the main battery 16 has a voltage of 3V or less of the voltage determination circuit BLDM.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

When the voltage of the main battery 16 drops to 3.0 V or less, the operation of the switching regulator 18 is stopped and the field effect transistor FET1 remains in the ON state. In this state, the BLDM from the voltage determination circuit BLDM
Output S7, becomes "L". As a result, the system controller 7 stops the CPU 2, followed by the CPU clock X1
Stop oscillating. At this time, the field effect transistor FE
T3 is turned off, and the field effect transistor FET4,
Circuit power supply VC from secondary battery 17 via diode D2
A current is supplied to C3, and the backup state is entered. At this time, no current flows through the circuit power supplies VCC1 and VCC2.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction content]

When the capacity of the main battery 16 is exhausted and the secondary battery 17 is further discharged and the circuit power supply VCC3 becomes 2 V or less, the output of the voltage determination circuit BLDL becomes "L" and the field effect transistor FET4 is turned off. Becomes After that, the current from the secondary battery 17 does not flow and over-discharge of the secondary battery is prevented.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0044

[Correction method] Change

[Correction content]

As a power source for the receiving section of the wireless block 12, the circuit power source VCC2 is opened and closed by the field effect transistor FET5. Similarly, the power supply of the transmission unit of the wireless block 12 opens and closes the circuit power supply VCC2 by the field effect transistor FET6. However, sudden circuit power VC at the start of transmission
Due to the load variation of C2 and the load variation on the wireless common portion, the wireless common power supply may vary, and the wireless transmission frequency may vary. To prevent this,
The gate of the field effect transistor FET6 is not directly driven at the same timing as the control signal TXBC, but feedback is applied from the output side through the resistor R8 through the capacitor C8 to make the rise gentle. In addition, the diode D3 is used to turn off the wireless transmission power supply quickly to prevent unnecessary radio waves from being emitted.
is necessary.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Name of item to be corrected] 0045

[Correction method] Change

[Correction content]

FIG. 6 is an explanatory diagram showing the relationship between the control signal TXBC and the radio transmission power source. The wireless transmission power supply starts rising almost linearly from the rise of the control signal TXBC. The time ΔT is determined by the time constants of the resistor 7 and the capacitor 7. Conventionally, as shown in FIG. 7, a capacitor R8
Was inserted between the resistor C8 and the ground. At this time, a time Td is required until the FET is turned on due to the threshold voltage of the field effect transistor FET6, and the rise is inferior in linearity as compared with FIG. In this way, the present invention can suppress fluctuations in the power supply and circuit load and maintain a stable frequency.

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0046

[Correction method] Change

[Correction content]

(Embodiment 2) FIG. 10 shows NM of the present invention.
FIG. 7 is a circuit diagram showing another embodiment of the I generation circuit 20. In this example, a reset generation circuit 21 is added for the sake of explanation.

[Procedure Amendment 16]

[Document name to be amended] Statement

[Correction target item name] 0047

[Correction method] Change

[Correction content]

Explaining the NMI generating circuit 20,
When the voltage of the main battery 16 rises above 3.4 V and the BLDH output S6 rises, a one-shot pulse determined by the time constant of the resistor R10 and the capacitor C9 is input to the AND gate Q4. The NMI signal S5 is output when the NMI inhibit signal S4 is "L" and the flip-flop FF2 is set by the initialization end signal S3.

[Procedure Amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction content]

[0049]

EFFECTS OF THE INVENTION From the above configuration, the present invention (1) separates the circuit power supply from VCC1 to VCC3 to use a switching regulator without being affected by ripple even in a wireless handy terminal.
As a result, the life of the battery can be extended. (2) By controlling the feedback of the switching regulator, the current of the entire circuit can be further reduced when the output current is small. (3) It is possible to extend the life of the secondary battery itself by constantly monitoring the voltage of the memory backup power supply and preventing over-discharge of the secondary battery when the secondary battery discharge end voltage is reached. , No need to replace batteries. (4) The voltage of the memory backup power supply is constantly monitored, and when the memory backup voltage is low, NMI operation after battery insertion or battery replacement is prohibited and reset to perform power-on reset and prevent malfunction of the device. . (5) When the main battery is removed by the time the initialization operation is completed immediately after resetting, the malfunction can be prevented by prohibiting the NIM operation and resetting when the voltage is restored thereafter. (6) By linearly raising the wireless transmission power supply, fluctuations in the power supply and circuit load can be suppressed and a stable frequency can be maintained. And so on.

[Procedure 18]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 10

[Correction method] Change

[Correction content]

FIG. 10 is a diagram showing a reset generation circuit 21 and an NM in the present invention.
FIG. 9 is a diagram showing another embodiment of the I generation circuit 20.

[Procedure Amendment 19]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 1 Power Supply Circuit 2 CPU 3 ROM 4 LCD Controller 5 RAM 6 Gate Array 7 System Controller 8 I / O Controller 9 RTC (Real Time Clock = Clock Function) 10 Key Switch 11 Buzzer 12 Wireless Block 13 Transfer Coil 14 EL ( Electroluminescence ) 15 Display (liquid crystal panel etc.) 16 Main battery 17 Secondary battery 18 Switching regulator 19 Reference power supply 20 NMI generation time 21 Reset generation circuit 22 Analog circuit 23 Digital circuit

Claims (6)

[Claims] 1. A ripple noise component of the switching regulator in a portable terminal equipped with a battery-operated switching regulator as a power source and a secondary battery for memory backup charged by the power source through a backup circuit. In order to reduce the power consumption of the portable terminal as a whole, the feedback circuit is provided with a switching element, and when the current consumption of the portable terminal is small, the switching element is turned off to cut off the ripple noise component from the output voltage. A power supply circuit for a portable terminal, characterized by 2. A portable terminal having a secondary battery for memory backup, wherein a voltage judgment circuit is provided, and the power supply voltage is constantly monitored by the voltage judgment circuit, and the power supply voltage drops below a predetermined voltage. The power supply circuit of the portable terminal according to claim 1, wherein the secondary battery is disconnected from the backup circuit when the power supply is turned on. 3. The portable terminal according to claim 2, wherein the higher voltage of the minimum voltage for the power supply for memory backup or the discharge end voltage of the secondary battery is the predetermined voltage. Power circuit. 4. A portable terminal equipped with a battery-powered switching regulator as a power source, a secondary battery for memory backup charged by the power source via a backup circuit, and a wireless transmission circuit, A transistor or a field effect transistor for opening and closing the power supply of the wireless transmission circuit is provided, and a resistor is connected between the base or gate of the transistor or field effect transistor and its control signal, and the base or gate and collector or drain are connected. The power supply circuit of the portable terminal according to claim 1, wherein a power supply circuit of the opened / closed wireless transmission circuit is controlled by connecting a capacitor between the power supply circuit and the output of the power supply, and performing feedback. 5. A memory backup circuit of a portable terminal, wherein the memory backup circuit has a storage circuit such as a flip-flop and at least two voltage determination circuits, and the determination voltage of the voltage determination circuit is The low voltage determination circuit monitors whether or not the power supply voltage during memory backup is equal to or lower than a predetermined voltage required for memory backup. In the voltage determination circuit having a high determination voltage, the main battery is a portable terminal. 4. A CPU is reset when the battery voltage rises from a low judgment voltage to a high judgment voltage by monitoring whether or not it has reached a voltage higher than that required for the operation of the machine. A power supply circuit for the portable terminal described. 6. A memory backup circuit of a portable terminal, wherein the memory backup circuit has a storage circuit such as a flip-flop, a voltage determination circuit, and an initialization completion signal, and the voltage determination circuit is a main battery. A state in which the initialization completion signal is output when the voltage required for the operation of the portable terminal device is monitored, and when the battery voltage reaches a high voltage equal to or higher than the determination voltage of the voltage determination circuit from a low voltage state. 4. The power supply circuit for the portable terminal according to claim 3, wherein NMI is applied to the CPU, and reset is applied when the initialization completion signal is not output.