JPH08294235A - Voltage decision circuit - Google Patents

Abstract

PURPOSE: To detect the battery voltage, which fluctuates depending on the type of battery being loaded or the load on the circuit section, accurately by outputting the results of collation between the average value of voltage over a predetermined period and a preset voltage reference. CONSTITUTION: A CPU 14 incorporates a memory section, i.e., an ROM, storing a table listing the reference value VREF and the hysteresis width AV of battery voltage VBAT for a primary voltage 11 and a secondary voltage 12 in light load mode and operating mode. The CPU 14 actuates a control operation in response to a digital value a1 delivered from an A/D converter 13, a secondary battery detection signal (b) and an operation mode signal (d) delivered from a radio circuit. The CPU 14 further calculates the average value VAVE of battery voltage VBAT of the primary battery 11 or the secondary battery 12 loaded between terminals A, B over one period thereof. The average value VAVE is collated with a reference voltage and the collation results, indicative of whether the battery is usable or not, are presented at a display section 15 comprising a liquid crystal display panel, for example.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage determination circuit applied to a wireless telephone device such as a digital portable telephone or a digital cordless telephone.

[0002]

2. Description of the Related Art Conventionally, in small portable electronic devices, a comparator system is used as a means for detecting the battery voltage of a primary battery or a secondary battery as a power source and determining whether or not this battery can be used. It is generally done.

In other words, this comparator system uses a measured battery voltage VBAT and a preset reference voltage value VRE.
F is compared with, for example, "H" level if the battery voltage VBAT is higher, and "L" if the reference voltage value VREF is higher.
A level detection signal is output to determine whether or not the installed battery is still usable. Further, in this comparator system, in order to prevent an error in the determination due to a minute fluctuation of the battery voltage VBAT,
A hysteresis width (allowable range) ΔV of about 50 mV to 100 mV is provided for the reference voltage value VREF, and the set reference voltage value VREF and hysteresis width ΔV are fixed in advance.

[0004]

By the way, when a secondary battery is used as a power source in an electronic device having a circuit driven at a constant cycle interval, such as a digital mobile phone,
In the light load mode such as the standby state shown in FIG. 4A, the fluctuation waveform of the battery voltage and the fluctuation waveform of the battery voltage in the operation mode such as the talking state shown in FIG. That is, it can be seen that the fluctuation waveforms of the battery voltage greatly differ depending on the mode, ie, the battery voltage for the operation in the light load mode and the battery voltage for the transmission of II, ie, the operation in the operation mode.

Particularly in the operation mode, the operating voltage of the circuit is extremely increased or decreased in a burst form due to the transmission of radio waves.
Correspondingly, the battery voltage VBAT also fluctuates greatly, so even if the battery voltage is detected by the conventional comparator method, the lowest point of the battery voltage VBAT may temporarily fall below the hysteresis width ΔV, resulting in erroneous detection. As a result, there is a problem that the operation of the circuit may be hindered.

Further, FIG. 5 shows a variation waveform of each battery voltage in a light load mode and an operation mode in a digital type mobile phone using a primary battery as a power source instead of the above FIG. Even in this case, since the battery voltage VBAT varies greatly in accordance with the operating voltage in each mode, the same result is produced.

Further, in a mobile phone in which both a primary battery and a secondary battery can be mounted, the internal resistance of the mobile phone also differs depending on the specifications of the battery, so the respective minimum operating voltages also differ.

As described above, in the conventional battery voltage detection method using the comparator system, it may be difficult to perform accurate detection because the battery voltage significantly changes depending on the type of battery and the load in each mode. There was that.

The present invention has been made in view of the above circumstances, and an object of the present invention is to accurately detect a battery voltage that fluctuates depending on the type of the installed battery and the load on the circuit part, and install the battery. It is an object of the present invention to provide a voltage determination circuit capable of determining whether or not a stored battery is still usable.

[0010]

Means for Solving the Problems That is, according to the present invention, in a voltage determination circuit, (1) measuring means for measuring a voltage consumed in a circuit portion driven at a constant cycle interval, and a voltage obtained by this measuring means. And a calculating means for calculating an average value in the above-mentioned constant cycle interval,
Collating means for collating the average value of the voltages calculated by the calculating means at the constant cycle intervals with a predetermined reference voltage set in advance, and output means for outputting the collation result by the collating means. It was done like this. (2) In addition to the above item (1), a detection means for detecting the drive mode of the circuit portion, and a storage means for storing the reference voltage corresponding to each drive mode in the circuit portion, the detection means. According to the result, the corresponding reference voltage is read out from the storage means and set.

[0011]

With the configuration shown in the above item (1),
Since the voltage of the attached battery is accurately detected regardless of the load of the circuit portion, it is possible to easily determine whether or not the battery can still supply power.

By adopting the structure shown in the above (2), in addition to the operation described in the above (1), the voltage of the installed battery can be accurately measured in consideration of the load on the circuit section according to the drive mode. Can be detected.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention applied to a portable wireless device will be described below with reference to the drawings. FIG. 1 shows its circuit configuration. 10 is a battery voltage detection device for a battery mounted in a portable wireless device, and 11 is this battery voltage detection device 1.
A primary battery as a power source attached to 0 and a secondary battery 12 are provided.

That is, the battery voltage detecting device 10 detects the battery voltage by mounting the primary battery 11 or the secondary battery 12, while using the battery voltage of the mounted primary battery 11 or the secondary battery 12 as a power source. Not supplied to the wireless circuit section (only shown as "circuit section" in the figure)
Basically, it is a four-terminal circuit having terminals A and B for connecting the primary battery 11 or the secondary battery 12 and terminals D and E for connecting to a circuit part (not shown), and further between the terminals A and B. Is provided with a terminal C as a fifth terminal for determining the type of the attached battery.

On the other hand, the primary battery 11 has the terminal A
, A negative terminal G corresponding to the terminal B, and a terminal H corresponding to the terminal C. This terminal H is a terminal for supplying the intermediate voltage of the primary battery 11, and the voltage generated at the positive terminal F of the primary battery 11 is VBA.
If the voltage is T, the voltage generated at the terminal H is, for example, VBAT
X (2/3).

The secondary battery 12 has only the positive terminal I corresponding to the terminal A and the negative terminal J corresponding to the terminal B, and does not have the terminal corresponding to the terminal C.

In the battery voltage detecting device 10, the terminal A is connected to one end of each of the resistors R2 and R3, the A / D converter 13, the anode of the diode D1 and the terminal D, and the terminal B is connected to each of the resistors R5 and R4. One end, the emitter of the NPN transistor Tr1, the A / D converter 13, C
It is connected to the PU 14 and the terminal E.

The cathode of the diode D1 is C
PU14 and electrolytic capacitor C1 whose negative end is grounded
Connected to the positive end of. Further, the terminal C is connected to the base of the transistor Tr1 and the resistor R1 via the resistor R1.
5 and the collector of the transistor Tr1 is connected to the other end of the resistor R2.

The potential at the connection point between the collector of the transistor Tr1 and the resistor R2 is given to the CPU 14 as a secondary battery detection signal b. Further, the resistors R3 and R
The other ends of the respective 4 are connected, and the potential at the connection point is given to the A / D converter 13.

The A / D converter 13 digitizes the voltage VBAT between the terminals A and B when the primary battery 11 or the secondary battery 12 is mounted by appropriately sampling the sampling frequency and the number of quantization bits, and digitizing it. The digital value a is sent to the CPU 14.

The CPU 14 is a storage unit that stores a table consisting of the reference value VREF of the battery voltage VBAT and the hysteresis width ΔV in the light load mode and the operation mode of the primary battery 11 and the secondary battery 12 as shown in FIG. As a built-in ROM, which will be described later in response to a digital value a from the A / D converter 13, the secondary battery detection signal b, and an operation mode signal d sent from a wireless circuit unit (not shown). The average value VAVE for one cycle of the battery voltage VBAT of the primary battery 11 or the secondary battery 12 attached to the terminals A and B is calculated and compared with the reference voltage to determine whether or not this battery can be used. The determination result is sent to and displayed on the display unit 15 including, for example, a liquid crystal display panel.

The diode D1 and the electrolytic capacitor C
1 is for guaranteeing the operation of the CPU 14 when the battery voltage VBAT is low, and the voltage charged in the electrolytic capacitor C1 is supplied to the CPU 14.

Next, the operation of the above embodiment will be described.
FIG. 3 shows a series of control operations mainly by the CPU 14 of the battery voltage detection device 10. When either the primary battery 11 or the secondary battery 12 is initially installed between the terminals A and B (step S1), the CPU 14 determines which one is installed based on the level of the secondary battery detection signal b. (Step S2).

That is, when the primary battery 11 is mounted, the terminal H is connected to the terminal C to turn on the transistor Tr1 through the resistor R1. Therefore, the battery voltage VBAT applied to the terminal A is The secondary battery detection signal b becomes "L" level through the transistor Tr1.

On the contrary, when the secondary battery 12 is attached, the corresponding terminal is not connected to the terminal C and is open, so that the transistor Tr1 is turned off and the secondary battery detection signal b indicates the battery voltage VBAT. The potential becomes "H" level as it is.

Therefore, if the secondary battery detection signal b is at "L" level, the CPU 14 connects the primary battery 1 between the terminals A and B.
If 1 is the “H” level, it is determined that the secondary battery 12 is installed, and the light load mode is determined from the table of the built-in ROM shown in FIG. 2 according to the determined battery type. The reference value V REF and the hysteresis width ΔV for each of the time and the operation mode are extracted (steps S3, S
4).

Thereafter, the battery voltage VBAT of the mounted primary battery 11 or secondary battery 12 is divided by resistors R3 and R4, and the value is digitized by the A / D converter 13 to sample the battery voltage VBAT. CPU14 that obtained the value a
Calculates the average value VAVE of the battery voltage VBAT for one cycle by averaging the sample value a for one cycle (step S5).

For example, to describe in more detail with reference to FIGS. 4 and 5, VBAT, which fluctuates once per cycle in the light load mode and twice in the operation mode, is converted into digital data as sample values, and the average value is calculated. That is, the value of VAVE is calculated.

Next, the CPU 14 determines whether or not the current operation mode is the operation mode signal d from the wireless circuit section (step S6), and if it is the operation mode, the contents extracted in the above step S3 or S4. The reference value VREF and the hysteresis width ΔV in the operation mode from among the
And a hysteresis width ΔV (steps S7, S
8).

Then, the selected reference value VREF and the hysteresis width ΔV are compared and collated with the average value VAVE of the battery voltage VBAT calculated in step S5 (step S).
9).

Then, the reference value VRE in the detected mode
It is judged whether or not the calculated average value VAVE of the battery voltage is lower than the allowable range indicated by the hysteresis width ΔV of F (step S10). If the average value VAVE is lower as a result, this battery cannot be used. Display unit 15
Is displayed (step S11), otherwise, after a certain period of time, the average value V of one cycle of the battery voltage VBAT is again displayed.
Enter the step of calculating AVE.

In step S10, the reference value VREF, the hysteresis width ΔV and the average value VAVE of the battery voltage are simply compared and collated, and only the result indicating whether or not the average value VAVE is lower than the reference value VREF is displayed and output. I decided to
For example, the curves of the voltage-life characteristics in each mode of the primary battery and the secondary battery are stored, and the average value VAV of the battery voltage is stored.
From the value of E, the remaining capacity of the installed battery may be calculated and added and displayed.Furthermore, if the remaining capacity is symbolically displayed and displayed, the It becomes easy to recognize.

Further, in the present embodiment, the case where the present invention is applied to the portable wireless device is illustrated, but the present invention is not limited to this, and a battery is used as a power source, a plurality of types of batteries can be used, and a plurality of operation modes having different loads are provided. Of course, it can be applied to the power supply circuit of the device.

[0034]

As described above in detail, according to the present invention, the voltage of the installed battery is accurately detected, and the power is supplied by the battery while sufficiently considering the type of the installed battery and the fluctuation of the load. Therefore, it is possible to provide a voltage determination circuit capable of always performing stable power supply in order to easily determine whether or not it is possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit configuration according to an embodiment of the present invention.

2 is a diagram exemplifying a table stored in a ROM incorporated in the CPU of FIG. 1. FIG.

FIG. 3 is a flowchart showing an operation content according to the embodiment.

FIG. 4 is a diagram exemplifying a fluctuation waveform of a battery voltage when a digital portable wireless device is driven by a secondary battery.

FIG. 5 is a diagram exemplifying a fluctuation waveform of a battery voltage when a digital portable wireless device is driven by a primary battery.

[Explanation of symbols]

 10 ... Battery voltage detection device 11 ... Primary battery 12 ... Secondary battery 13 ... A / D converter 14 ... CPU 15 ... Display unit

Claims (2)

[Claims] 1. A measuring means for measuring a voltage consumed in a circuit section driven at a constant cycle interval, and a calculating means for calculating an average value of the voltage obtained by the measuring means at the constant cycle interval, Collating means for collating the average value of the voltages calculated by the calculating means at the constant cycle interval with a predetermined reference voltage set in advance, and output means for outputting the collation result by the collating means. A voltage determination circuit characterized by the above. 2. A detection means for detecting a drive mode of the circuit portion, and a storage means for storing the reference voltage corresponding to each drive mode in the circuit portion, the storage means according to a result of the detection means. 2. The corresponding reference voltage is read out from the device and set.
The voltage determination circuit described.