JPH0640433Y2 - Output mode control circuit for AC adapter that also functions as a charger - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] In addition to the function of an AC adapter that connects to an AC power source and supplies DC output to various electronic devices such as a video camera,
The present invention relates to an output mode control circuit for a charger / AC adapter that has a function of charging a storage battery.

[Prior art and its problems]

This kind of AC adapter is designed to obtain different output modes of different current and voltage for the charger and the original function of the AC adapter.

To change the output mode for the AC adapter that functions as a charger, remove the storage battery from the output terminal of the AC adapter except when the attached storage battery is fully charged. However, changing the output mode by removing the storage battery from the AC adapter is troublesome considering the case where the storage battery is temporarily stopped to change the output mode in order to operate the electronic device such as a video camera. Therefore, it is desirable to be able to change it while the storage battery is connected to the AC adapter.

〔Purpose〕

An object of the present invention is to provide an output mode control circuit for a charger / AC adapter that can forcibly change the output mode by a switch from outside the AC adapter.

[Technical means for solving problems]

The output mode control circuit of the AC adapter that also functions as a charger according to the present invention is a switching circuit for selecting either the output mode for the charger or the AC adapter, and an instruction circuit for instructing the switching circuit to change the output mode from the outside. A switching circuit in a state in which the instruction circuit, the first detection circuit, and the second detection circuit are OR-connected. And the first detection circuit and the second detection circuit operate only when the switching circuit responds to the instruction circuit to select the output mode for the charger.

〔Example〕

Hereinafter, an embodiment of an output mode control circuit of a charger / AC adapter of the present invention will be described with reference to FIG. 1, which is a block diagram.

In FIG. 1, 1 is a first detection circuit for detecting the charging completion state of the storage battery, 2 is a second detection circuit for detecting the presence or absence of the AC adapter of the storage battery, and 3 is a charger and an AC adapter. A switching circuit for selecting one of the output modes, 4 includes a switch, an instruction circuit for instructing the switching circuit 3 to change the output mode from the outside of the AC adapter, and 5 a time setting circuit for setting the charging time. is there. Switching circuit 3
Connects to a DC source to obtain a DC output. In the case of a nickel-cadmium storage battery, the first detection circuit 1 is preferably a -ΔV circuit.

The instruction circuit 4, the first detection circuit 1, the second detection circuit 2,
The output terminal of the time setting circuit 5 is connected to the switching circuit 3 in an OR-connected state.

Here, the output signals of the above-mentioned four circuits are set to a reference state (for example, 0 [V]) as a charging signal for requesting the switching circuit 3 to output for charging, and other states (for example, E [V]) are switched. This is a binary signal which is an adapter signal for requesting the output mode for the AC adapter to the circuit 3. And in Figure 1 OR
In the state of OR connection of each circuit represented as a circuit, the charging signal output by each circuit is considered to be the reference level (“0”) and the adapter signal is considered to be the logical signal level (“1”).

The ac adapter that also serves as a charger is equipped with an uncharged storage battery, and when the battery is just installed and the mode is for the charger, the four circuits output charge signals to the switching circuit 3 respectively. Is charged with a charging signal. Therefore, the switching circuit 3 uses the output mode for the charger.

The first detection circuit 1 outputs an adapter signal instead of the charging signal when detecting the completion of charging the storage battery. Similarly, when the second detection circuit 2 detects a state in which the storage battery is not attached, when the instruction circuit 4 is changed to the function of the AC adapter, and when the time setting circuit 5 detects the passage of a predetermined time. , Each circuit outputs an adapter signal.

The output terminals of the first detection circuit 1, the second detection circuit 2, and the instruction circuit 5 are connected to the switching circuit 3 in an OR-connected state. Therefore, when any one of the circuits outputs the adapter signal requesting the output mode for the AC adapter, the adapter signal is input to the switching circuit 3 instead of the charging signal up to that point. As a result, the switching circuit 3 switches the output mode for the AC adapter. Therefore, the switching circuit 3 selecting the output mode for the charger changes the selection to the output mode for the AC adaptor, not to mention the instruction circuit 4, and the signal from any other OR-connected circuit. .

Here, when the instruction circuit 4 is set to function as an AC adapter, the instruction circuit 4 outputs an adapter signal to the switching circuit 3 and at the same time, the first detection circuit 1, the second detection circuit 2, and the time A signal for stopping the operation is output to the setting circuit 5. As a result, the three circuits stop operating, wasteful power consumption is suppressed, and malfunction can be prevented.

On the other hand, when the instruction circuit 4 functions as an AC adapter,
The switching circuit 3, which is in the output mode for the AC adapter,
The output mode can be changed for the charger only by the signal from the indicator circuit 4.

FIG. 2 is a block diagram showing another embodiment of the output mode control circuit of the AC adapter for both charger and battery of the present invention. The same parts as those in FIG. 1 are designated by the same reference numerals.

In FIG. 2, the first detection circuit 1 and the second detection circuit 2 are connected directly to the time setting circuit 5 in an OR connection. Then, with the instruction circuit 4 and the time setting circuit 5 being OR-connected, the switching circuit 3
Connect to. The first detection circuit 1, the second detection circuit 2, and the time setting circuit 5 operate only when the switching circuit 3 selects the output mode for the charger, as in the case of FIG.

Although the instruction circuit 4 and the time setting circuit 5 are connected to the switching circuit 3 in an OR-connected state, the instruction circuit 4, the first detection circuit 1, and the second detection circuit 2 are indirectly connected in FIG. OR connected.

Therefore, when the switching circuit 3 is selecting the output mode for the charger, when the time setting circuit 5 is reset by the signal of either the first detection circuit 1 or the second detection circuit 2, In either case of generating a signal indicating the end of the charging time or in the case of a signal from the indicating circuit 4, the switching circuit 3 changes its output mode selection to that for the AC adapter.

When the instruction circuit 4 functions as the AC adapter, the switching circuit 3 in the output mode for the AC adapter can change the output mode for the charger only by the signal from the instruction circuit 4. The OR connection state of the instruction circuit 4, the first detection circuit 1, and the second detection circuit 2 includes indirect connection via the time setting circuit 5 as shown in FIG. 2, but in addition to this, the first detection circuit 1
Alternatively, the time setting circuit 5, the second detection circuit 2, and the instruction circuit 4 connected to each other may be OR-connected. The time setting circuit 5 is not always necessary for the control circuit of the present invention and may be omitted.

〔effect〕

As described above, the output mode control circuit of the charger / AC adapter of the present invention is connected to the switching circuit that selects the output mode with the indicator circuit, the first detection circuit, and the second detection circuit being OR-connected. There is. The output circuit in the form of a switch allows the output mode to be changed freely while the storage battery or electronic device is still connected to the AC adapter, eliminating the hassle of removing the storage battery from the AC adapter with each change. It is convenient to handle because it can be omitted.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an output control circuit of a charger / AC adapter of the present invention, and FIG. 2 is a block diagram showing another embodiment. 1: First detection circuit, 2: Second detection circuit 3: Switching circuit, 4: Indicator circuit

Claims (1)

[Scope of utility model registration request] 1. A switching circuit for selecting one of an output mode for a charger and an AC adapter, an instruction circuit for externally instructing the switching circuit to change the output mode, and a completion state of charging of a storage battery is detected. The detection circuit includes a first detection circuit and a second detection circuit that detects the presence or absence of a storage battery, and the instruction circuit, the first detection circuit, and the second detection circuit are connected to the switching circuit in an OR-connected state, and the first detection circuit and An output mode control circuit for a charger / AC adapter, wherein the second detection circuit operates only when the switching circuit responds to the instruction circuit and selects the output mode for the charger.