JP3468483B2 - Automatic voltage switching method and device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply voltage automatic switching circuit, and more particularly to a power supply voltage automatic switching method and device for switching the power supply voltage of a switching regulator for low voltage and high voltage.

[0002]

2. Description of the Related Art In recent years, an increasing number of electronic devices have a built-in switching regulator so that they can be operated simply by connecting a commercial AC power source. In this case, a switching regulator for the AC power supply voltage having a voltage according to the destination country or the like or the application is used.

When a plurality of types of electronic devices are mixedly produced under such circumstances, electronic devices having switching regulators with different power supply voltages flow through the production line. Therefore, for example, an electronic device equipped with a switching regulator for AC100V and AC200V
In the case of mixed production of electronic equipment equipped with a switching regulator for power supply, in order to inspect the function of each electronic equipment, conventionally, the AC100V power supply device and the AC200V power supply device are exchange-connected according to the working voltage of the switching regulator. Then, the voltage was supplied.

[0004]

However, when the power supply device is exchanged and connected according to the power supply voltage of the switching regulator as in the prior art, not only complicated work is required, but also if the wrong power supply is mistakenly used. If the device is connected and the high-voltage power supply voltage is supplied to the switching regulator for the low-voltage power supply, the parts of the electronic device may be destroyed, so it is necessary to pay close attention to the handling.

For example, when a power supply voltage of AC100V is supplied to a switching regulator for AC200V, only an inrush current flows, so that there is no fear of destroying parts. On the other hand, a power supply voltage of AC200V is supplied to a switching regulator for AC100V. If it happens, the parts will be destroyed in a wide range.

[0006] In Japanese Utility Model Laid-Open No. 2-111818, a voltage switching circuit is built in the electronic equipment so that the user can immediately switch to a proper voltage regardless of whether the user connects a high voltage or low voltage AC power source. A configuration adapted to deal with the problem is disclosed. However, adding the voltage adjusting circuit as described above to each electronic device in addition to the switching regulator increases cost, and not all electronic devices are provided with such a circuit. You cannot solve the problem.

Further, since the voltage switching circuit as described above is provided in each individual electronic device, it is configured to switch to an input voltage specific to the electronic device to which the electronic device is applied. Is detected, and when the detection result is not the voltage unique to the electronic device,
The input voltage is configured to be switched to a specific voltage.

However, when it is necessary to supply different voltages depending on the type of electronic equipment or the destination country as described above, the voltage switching circuit as described above cannot be applied.

The present invention has been proposed in view of the above-mentioned conventional circumstances, and when a plurality of types of electronic devices equipped with switching regulators for different AC voltages are mixedly produced, an appropriate AC voltage is automatically set. It is an object of the present invention to provide an automatic voltage switching method and device capable of quickly supplying a power supply and inspecting functions and the like.

[0010]

The present invention employs the following means in order to achieve the above object. That is, according to the difference in the length of time from the rise to the fall of the input current when the power supply of the proper pressure is applied to the switching regulator and when the power supply of the voltage lower than the proper pressure is applied, the switching is performed. The power supply voltage of the regulator is switched.

In order to realize the above method, the present invention is, as shown in FIG. 1, an input detecting means 100 for detecting an input current to a switching regulator 20 to which a low voltage power source is applied.
And a time discriminating means 200 for discriminating whether or not the time from the rise to the fall of the output of the input detecting means 100 is a predetermined time or more, and when the output of the time discriminating means 200 is longer than the predetermined time. Keep the low voltage power applied,
If it is short, it is composed of voltage switching control means 300 for switching and controlling the applied state to the high voltage power supply, and power supply voltage selection means 400 for selectively switching the low voltage power supply and the high voltage power supply controlled by the voltage switching control means 300. There is.

Further, the time discriminating means 200 includes a timer 23 for counting a predetermined time from the rising of the output of the input detecting means 100, a rising detecting means 24 for detecting the rising of the output of the input detecting means 100, and the input. Detection means 1
Fall detection means 26 for detecting the fall of the output of 00,
A switch means Q ₆ is provided which activates the voltage switching control means 300 by allowing a fall signal generated within the predetermined time from the rise of the output of the rise detection means 24 to pass through.

[0013]

When a proper power supply voltage is applied to the switching regulator, a predetermined current will continue to flow, but if the applied power supply voltage is extremely low (for example, half), the power supply voltage Only the inrush current will flow at the moment when is applied.

Therefore, the power supply voltage selecting means 400 is initially set to a low voltage power supply (100V). When the low-voltage switching regulator 20 is connected in this state, the input detection means 100 sets its output to "H" and continues that state.

The time discriminating means 200 is the input detecting means 1
When it is determined that the "H" output of 00 is longer than the predetermined time, it means that the switching regulator 20 having an appropriate voltage is connected.
It is not necessary to change the above initial state of. Therefore, at this time, the voltage switching control means 300 does not operate.

When a power supply voltage significantly lower than the proper voltage is applied to the switching regulator 20,
Only an inrush current flows through the switching regulator 20, so that the output of the input detecting means 100 is "H" for a short time corresponding thereto. Therefore, when the time determination means 200 determines that the "H" output of the input detection means 100 is shorter than the predetermined time, it means that the switching regulator 20 for the high-voltage power supply is connected, so the voltage switching control means 300 The power supply voltage selection means 400 is set to the high voltage power supply selection state.

[0017]

FIG. 2 is a block diagram of an embodiment of the present invention, FIG. 3 is a time chart when a switching regulator for low voltage (for example, AC100V) is connected, and FIG. 4 is high voltage (for example, AC2).
10 is a time chart when a switching regulator for (00V) is connected.

Relay R as power supply voltage selecting means 400
L1 selects the low voltage power source as the initial state. In this state, the low-voltage power supply switching regulator 20 is connected to the low-voltage power supply via the misconnection notification buzzer 10 and the relay RL1.

Here, when the switch SW of the switching regulator 20 is turned on at time t ₁₀ as shown in FIG. 3 (a), the AC low voltage current flowing through the relay RL1 is input to the switching regulator 20 and The detection coil 13 constituting the detection means 100 inputs the current to the current detection means 11 to detect the current.

As shown in FIG. 3D, this output is input to the comparator 12, converted into an appropriate voltage, and input to the rising edge detecting means 24 constituting the time discriminating means 200. As a result, the rise detecting means 24 detects the rise of the current (FIG. 3 (c)) flowing in the line when the switch of the switching regulator 20 is turned on, and the output thereof becomes "H" as shown in FIG. 3 (e). To This rising detection means 2
The "H" output of No. 4 is reset by the fall delay reset means 25 described later.

The timer 23 is started by the rise of the current detected by the current detecting means 11, and the predetermined time t
Count ₁ (eg 200 ms). When the timer 23 counts the predetermined time t ₁ , as shown in FIG. 3 (h), its output is raised, and at this time, the switch Q ₆ is turned off to shut off the output of the fall detection means 26. This state is reset by the fall delay reset means 25 described later.

Next, when the switch SW of the switching regulator 20 is turned off at time t ₁₁ , the relay RL1
The current that flows through is also turned off. As a result, when the output of the comparator 12 shown in FIG. 3 (d) falls to "L" (after the output of the current detecting means 11 becomes "L", a predetermined time t ₀ [depends on the time constant in the comparator 12). For example
100 ms] and falls, and the fall detection means 26 detects the fall and sets its output to "H" as shown in FIG. 3 (f). The state of the fall detection means 26 continues until the output of the comparator 12 rises to "H" again or the rise detection means 24 is reset by the fall delay reset means 25.

The output of the fall detection means 26 is input to the voltage switching control means 300 as long as the switch Q ₆ in the next stage is on. The switch Q ₆ is operating the timer 23 (the output of the timer 23). Is "L"). Therefore, when the low-voltage switching regulator 20 is connected as described above, the switch Q ₆ does not turn on when the fall detection means 26 is "H", so the relay RL1 is low-voltage. Maintain power supply.

The output of the comparator 12 is also input to the falling delay resetting means 25, and when the output of the comparator 12 rises, the output of the falling delay resetting means 25 is once "L" as shown in FIG. 3 (j). Becomes Next, when the output of the comparator 12 falls, after a predetermined time t ₂ (20 in FIG. 3).
After 0 ms), the rise detection means 24, the timer 23 and the voltage switching control means 300 are reset.

FIG. 4 shows a time chart when a switching regulator for high voltage (for example, 200 V) is connected. First, the contact of the relay RL1 is initially set to the low voltage side, and this state does not change even when the switching regulator 20 for high voltage is connected. However, with the low voltage power supply connected to the high voltage switching regulator 20, the switching regulator 20
When the switch SW is turned on, the time t in FIG.
_As shown in ₂₀ , only inrush current flows. The voltage corresponding to this inrush current is, as shown in FIG.
2 at a predetermined time (i.e. the time corresponding to the time constant of the comparator 12) t ₀ is held, it falls.

As shown in FIG. 4 (e), the rising detecting means 24 in the next stage raises its output in response to the inrush current and resets the falling delay as in the case of using the low voltage power source. It is reset by means 25.

On the other hand, the trailing edge detecting means 26 receives the comparator output shown in FIG. 4 (d) which falls after the elapse of the predetermined time t _0, and raises its output as shown in FIG. 4 (f).
On the other hand, the timer 23 is activated by the rising output of the comparator 12 at the time t ₂₀ , and its output is started after counting the predetermined time t ₁ . Since the set time t ₁ of the timer 23 is set to a value larger than the predetermined time t ₀ corresponding to the time constant of the comparator 12, when the fall detection means 26 becomes "H" as described above. The switch Q ₆ is on, and the output of the fall detection means 26 is input to the voltage switching control means 300, as shown in FIG. 4 (i).

As a result, the voltage switching control means 300 switches the relay RL1 from the low-voltage power source to the high-voltage power source, and the high-voltage switching informing means 31 informs accordingly. After that, the high voltage power supply application state is maintained until the voltage switching control means 300 is reset by the falling delay reset means 25. When switched in this manner in the high power, then the output of comparator 12 again as shown at time t ₃₀ in FIG. 4 "H" and the output of the trailing edge detection means "L"
Becomes

Here, the falling output of the comparator 12 is also input to the falling delay resetting means 25, but a predetermined time (the time from the falling of the comparator 12 until the falling delay resetting means 25 rises). since the "H" again at the (time t ₃₀₎ within t _2, the output of the fall delay reset unit 25 does not become also "H" after the predetermined time t _2, therefore, rise detecting means 24, The timer 23 and the voltage switching control means 300 are not reset.
In FIG. 4, the timer setting time t ₁ and the predetermined time t ₂ are designed to have the same value. The operation after the switch SW of the switching regulator 20 is turned off is the same as that shown in FIG.

The erroneous connection notification buzzer 10 is provided on the low-voltage line, and an alarm is issued when the high-voltage power source is connected to the low-voltage line to prevent the destruction of parts and the like. Has become.

[0031]

As described above, the present invention utilizes the fact that only a rush current flows when a switching regulator for a high-voltage power supply is connected to a low-voltage power supply, and whether the switching regulator to be tested is a low-voltage power supply or a high-voltage power supply is determined. Since the judgment is made and the power of the regular voltage is turned on, the regular voltage can be applied to the switching regulator easily and surely by an inexpensive circuit.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention.

FIG. 2 is a block diagram of an embodiment of the present invention.

FIG. 3 is a time chart of FIG.

FIG. 4 is a time chart of FIG.

[Explanation of symbols]

11 current detection means 12 comparator 20 switching regulator 23 timer 24 rise detection means 26 fall detection means 100 input detection means 200 time determination means 300 voltage switching control means 400 power supply voltage selection means Q ₆ switch means

Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G05F 1/00 G01R 19/00 G01R 29/027 H02M 3/00

Claims (3)

(57) [Claims] 1. Depending on the difference in the length of time from the rise to the fall of the input current when a power supply of a proper pressure is applied to the switching regulator and when a power supply of a voltage lower than the proper pressure is applied to the switching regulator. , A method for automatically switching the voltage for switching the power supply voltage of the switching regulator. 2. Input detection means for detecting an input current to a switching regulator to which a low voltage power supply is applied, and whether or not the time from the rise of the output of the input detection means to the fall is a predetermined time or more. And a voltage switching control means for maintaining the low-voltage power supply applied state when the output of the time determination means is longer than the predetermined time, and a voltage switching control means for switching the applied state to the high-voltage power supply when the output is short. An automatic voltage switching device comprising a power supply voltage selection means for selectively switching between a low voltage power supply and a high voltage power supply controlled by a control means. 3. A timer for the time discrimination means to count a predetermined time from the rise of the output of the input detection means, a rise detection means for detecting the rise of the output of the input detection means, and a rise of the output of the detection means. The falling detection means for detecting a falling, and a switching means for allowing a falling signal generated within the predetermined time from the rising of the output of the rising detection means to pass through and activating the voltage switching control means. Automatic voltage switching device.