JPH0318230A - Power supply equipment - Google Patents

Abstract

PURPOSE:To detect the actual operating voltage of electronics by detecting an operating voltage inward of the current input end on the electronics side through providing a detection connecting means besides a line for supplying an operating current from an power supply equipment to the electronics. CONSTITUTION:DC is supplied from the secondary rectifying and smoothing part 6 of AC adapter 1 to a load, e.g. the input terminal 22 of an electronic still camera 21 via cable 31. A stable power is supplied from the terminal 22 to a microcomputer 27 and a signal processing circuit 28 via protective circuit 23 for fuse, etc., and power supply circuit 24. On the other hand, a motor 25 and stroboscope 26 consuming a high current are directly supplied with power from the protective circuit 23. Also, cables 61, 62 are provided separately between the AC adapter 1 and camera 21, and one end of the cable 61 is connected to a point C inside the protective circuit for the camera and the other end to a voltage divider composed of resistances 8, 9 within the AC adapter 1, and the cable 62 is connected to the earth of the resistance 9 and camera 21. Thus, actual operating voltage within the camera are compared 10 and detected so that the operation of the camera is stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a power supply device, typified by an AC adapter, which smoothes a commercial AC voltage into a DC voltage and supplies the same to an electronic device such as an electronic still camera.

[Conventional technology]

FIG. 2 is a block diagram showing the connection relationship between a conventional AC adapter and an electronic still camera.

In the figure, 1 is an AC adapter, 21 is an electronic still camera, and output terminals 7 and 14 of the AC adapter 1 are connected to input terminals 22 and 29 of an electronic still camera 21 via cables 31 and 32, respectively. , DC voltage is supplied from the AC adapter 1 to the electronic still camera 2l.

The input terminal 22 of the electronic still camera 21 has a fuse, 2
It is connected to a power supply circuit 24 via a protection circuit 23 consisting of a diode or the like for preventing backflow when the next battery is used. The microcomputer 27 and signal processing circuit 28 are supplied with necessary power from this power supply circuit 24.

On the other hand, a protection circuit 23 is provided for the motor 25, strobe 26, etc.
The output voltage is supplied as is.

The AC adapter 1 is configured as shown in FIG. 3, for example.

In the figure, 2 is an input terminal into which a commercial AC voltage of 50 Hz, 60 Hz, etc. is input, and 3 is the noise that enters from the input terminal 2, or the inverter section 3--4 5 and the secondary rectification smoothing section 6. This is a line filter that suppresses feedback noise generated in a DC-DC converter. 4 is an l-order rectifying and smoothing section which rectifies and smoothes the output of the line filter 3 and outputs it to the inverter section 5.

The DC voltage output from the secondary rectification and smoothing section 6 is supplied to the output terminal 7, and a part of it is divided by resistors 8 and 9 connected between the terminals 7 and 14, and then sent to the comparison circuit section. 10
It is now entered into Reference numeral 11 denotes a reference voltage generation circuit, which supplies a reference voltage to the comparison circuit section 10.

Reference numeral 12 denotes an amplifier circuit section, which amplifies the output of the comparison circuit section 10 and supplies it to the control circuit section 13 in parallel. The control circuit section 13 is configured to control the inverter section 5 in response to a signal input from the amplifier circuit section l2.

Next, its operation will be explained.

The commercial AC voltage inputted from the input terminal 2 is inputted to the primary rectification and smoothing section 4 via the line filter 3, where it is rectified and smoothed. The l-order DC voltage output from the l-order rectifier and smoothing section 4 is inputted to the secondary rectifier and smoother 6 via the inverter section 5, where it is rectified and smoothed again. The secondary DC voltage output from the secondary rectifying and smoothing section 6 is supplied as the final DC voltage to the input terminal 22 of the electronic still camera 2 via the terminal 7 and the cable 31.

The DC voltage input to this input terminal 22 is transmitted to the protection circuit 2.
The voltage is inputted to the power supply circuit 24 via the power supply circuit 3, and further converted into a plurality of stable DC voltages to be supplied to each circuit, and supplied to the microcomputer 27, signal processing circuit 28, etc.

-4, the motor 25, the strobe 26, etc. consume a large amount of power and do not require a very stable voltage, so the voltage output from the protection circuit 23 is directly supplied to them without going through the power supply circuit 24.

The terminal 29 of the electronic still camera 21 is grounded inside, and the terminal 1 is grounded inside the AC adapter 1.
4 via a cable 32. As a result, the current used in the electronic still camera 21 is
It is designed to return to AC adapter 1.

In the electronic still camera 2, when the motor 25, strobe 26, etc. are used, their current consumption increases. As a result, the voltage at the output terminal 7 of the AC adapter drops due to the resistance of the lances and transistors forming the inverter section 5 and the choke coils forming the secondary rectification and smoothing section 6.

This voltage change is detected by the resistors 8 and 9, and the comparison circuit section 10
is input. The comparison circuit unit 10 compares the input voltage with the reference voltage output from the reference voltage generation circuit 1 and outputs the error voltage.

This error voltage is passed through the amplifier circuit section 2 to the control circuit section 13.
is input. The control circuit section 13 changes the duty ratio of the output control pulse in accordance with the input error voltage. The inverter unit 5 turns on and off internal switching elements in response to control pulses input from the control circuit unit 13. 1 output from the l-order rectification and smoothing section 4
The supply of the secondary DC voltage to the secondary rectifying and smoothing section 6 is interrupted in response to whether this switching element is turned on or off.

Therefore, the voltage output from the terminal 7 remains approximately constant regardless of the usage status of the electronic still camera 21.

[Problem to be solved by the invention]

However, in reality, the cables 3, 32 and the protection circuit 23 have resistance, which causes a voltage drop, so the operating voltage in the electronic still camera 2 is not necessarily constant.

This relationship will be explained below with reference to FIG.

In the electronic still camera 2, when the motor 25 is driven or the strobe 26 is charged, a current flows through the cable 3'' as shown in FIG. 4(b), for example. The peak value is 1 A or more when the motor 25 is charged, and 3 A or more when the strobe 26 is charged.

Even if the operating current changes in this way, the constant voltage servo is applied as described above, so if the ground potential of terminal 14 is used as a reference as shown in Figure 4(d), the voltage of terminal 7 will remain the same. It becomes constant as shown in Figure (a).

However, since there is a resistance component7-18 in the cable 31, the connector that makes up the terminal 22, the protection circuit 23, etc., the output voltage of the protection circuit 23 is reduced by the consumption as shown in FIG. 4(C). Changes in response to changes in current.

This change is particularly remarkable since electronic still cameras mainly operate intermittently, unlike camera-integrated video tape recorders and the like.

As described above, when the power supply voltage fluctuates, the operation becomes unstable and malfunctions are likely to occur.

For this reason, for example, the cables 31 and 32 are made thicker, the connectors are made larger, and a voltage higher than necessary is supplied with some margin.

As a result, the device becomes large and the cost becomes 1, which is disadvantageous.

This invention was made in view of this situation,
This makes it possible to maintain a constant power supply voltage and achieve stable operation regardless of usage conditions.

Furthermore, it is possible to realize a compact and low-cost device.

[Means to solve the problem]

The power supply device according to claim 1 of the present invention is a power supply device that rectifies and smoothes an AC voltage to generate a constant DC voltage and supplies this to an electronic device, the power supply device having a first output that outputs the DC voltage. a first connecting means that connects the terminal, a second output terminal that is grounded, a first input terminal into which a DC voltage of the electronic device is input, and a first output terminal; and a first connecting means that connects the first output terminal; a second connection means for connecting a second input terminal and a second output terminal; a first detection input terminal to which a detection signal for detecting the operating voltage of the electronic device is input; a second detection input terminal into which a detection signal for detecting the ground voltage of the electronic device is input; a first detection input terminal; and a first detection terminal connected to a detection point for detecting the working voltage of the electronic device. a third connection means for connecting the output terminal; and a fourth connection means for connecting the second detection input terminal and a second detection output terminal connected to a detection point for detecting the ground voltage of the electronic device. and a comparison circuit that compares the voltage between the first detection input terminal and the second detection input terminal with a reference value and controls the DC voltage according to the comparison result.

The invention according to claim 2 of the present invention is a power supply device that rectifies and smoothes an AC voltage to generate a constant DC voltage and supplies this to an electronic device, the power supply device having a first output terminal that outputs the DC voltage. a second output terminal that is grounded, a first input terminal to which a DC voltage of the electronic device is input, and a first output terminal; a second connection means for connecting a second input terminal and a second output terminal; a first detection input terminal to which a detection signal for detecting the operating voltage of the electronic device is input; a second detection input terminal into which a detection signal for detecting the ground voltage of the device is input, a third connection means for connecting the first detection input terminal and the first input terminal of the electronic device; Second
and a fourth connection means for connecting the detection input terminal of the electronic device to the second input terminal of the electronic device, and comparing the voltage between the first detection input terminal and the second detection input terminal with a reference value. and a comparison circuit that controls the DC voltage according to the result.

[Effect]

In the power supply device according to claim 1, the first
The output terminal and the second output terminal of the electronic device are connected to the first input terminal and the second input terminal of the electronic device by a first connection means and a second connection means made of, for example, a cable, and are connected to the power supply device. DC voltage is supplied to the electronic device ↓ The first detection output terminal of the electronic device is, for example, a fuse,
Connected to the output of a protection circuit consisting of a diode, etc. This first detection output terminal is connected to the first detection input terminal of the power supply device through a third connection means.

Further, the second detection output terminal of the electronic device is connected to, for example, a ground line. This second detection output terminal is connected to the second detection input terminal of the power supply device by a fourth connection means.

The voltage output from the first output terminal is controlled in accordance with the potential difference between the first detection input terminal and the second detection input terminal.

Therefore, the operating voltage of the electronic device can be held constant without being affected by the resistance values of the first connection means, the second connection means, the protection circuit of the electronic device, etc.

-11- -12- In the power supply device according to claim 2, the first
The output terminal and the second output terminal of the electronic device are connected to the first input terminal and the second input terminal of the electronic device by a first connection means and a second connection means consisting of, for example, a cable, DC voltage is supplied to electronic equipment from

The first detection input terminal of the power supply device is connected to the first input terminal of the electronic device by a third connection means. Further, the second detection input terminal of the power supply device is connected to the second input terminal of the electronic device by a fourth connection means.

The voltage output from the first output terminal is controlled in accordance with the potential difference between the first detection input terminal and the second detection input terminal.

Therefore, at least the first connecting means and the second connecting means.
The operating voltage of electronic devices can be held constant without being affected by the resistance value of the device.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the power supply device of the present invention, and parts corresponding to the numbers in FIGS. 2 and 3 are given the same reference numerals.

In FIG. 1, 41 and 42 are detection terminals provided on the AC adapter 1, and are connected to resistors 8 and 9, respectively. 51 and 52 are terminals provided on the electronic still camera 21, with the terminal 5 being connected to the output terminal of the protection circuit 23, and the terminal 52 being connected to an internal grounding wire, respectively.

61 is a cable connecting the detection terminal 4 of the AC adapter l and the terminal 5l of the electronic still camera 21;
is a cable that connects the detection terminal 42 of the AC adapter and the terminal 52 of the electronic still camera II.

The rest of the structure is the same as the conventional case described above, so a detailed description thereof will be omitted.

Next, in the 6-electronic camera 21 whose operation will be explained with reference to FIG. 5, by using the motor 25, the strobe 26, etc., the cable 31 is When current flows. Using the potential of the grounding wire connected to the terminal 14 of the AC adapter 1 as shown in FIG. 5(e) as a base, the voltage at the terminal 7 is as shown in FIG.
). Furthermore, the voltage at the output terminal of the protection circuit 23 is as shown in FIG.
The voltage of the ground line connected to 9 changes as shown in FIG. 9(f).

Current mainly flows through cables 3 and 32, and almost no current flows through cables 61 and 62. Therefore, the voltage of the output terminal of the protection circuit 23 and the voltage of the grounding wire connected to the terminal 29 are the same as those of the connectors forming the terminals 4]-, 42, 51-, 52, the cables 6, 62, etc. It is detected by resistors 8 and 9 almost unaffected by the resistance component.

The voltage at the connection point between the resistors 8 and 9 shown in FIG. 5(d) is compared with the base voltage generated by the base voltage generation circuit 1 in the comparator circuit section 10. As described above, the DC voltage output from the secondary rectification and smoothing section 6 is controlled in accordance with the difference from this reference voltage.

Therefore, the servo is applied so that the potential difference between the output terminal of the protection circuit 23 and the ground line connected to the terminal 29 matches the base voltage increase.

As a result, the difference between the voltage shown in FIG. 5(c) and the voltage shown in FIG. 5(f), that is, the operating voltage in the two electronic still cameras becomes approximately constant.

FIG. 6 is a block diagram showing the structure of another embodiment of the power supply device of the present invention, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the embodiment of FIG. 1, cables 61 and 62 are connected to terminals 51 and 52, respectively, and terminals 51 and 52 are connected to predetermined locations further inside the electronic still camera 2.

On the other hand, in the embodiment of FIG. 6, the terminals 5l and 52 are omitted, and the cables 61 and 62 are
9, respectively.

In the case of this embodiment, the influence due to the internal resistance of the protection circuit 23 and the connector that constitutes the terminals 22 and 29 cannot be avoided, but the influence of the internal resistance of the connector that constitutes the cables 31 and 32 and the terminals 7 and l4 cannot be avoided. The effects can be avoided.

15-16- Incidentally, in the above, the detected voltages were compared in an analog manner, but they may be processed digitally. Also A
There is one voltage value output from C adapter 1 (for example, 5V
), but the present invention can be applied even if the voltage is 2 or more (for example, 5V and 12V).

〔Effect of the invention〕

As described above, according to the power supply device according to claim 1 of the present invention, in addition to the connection means for supplying operating current from the power supply device to the electronic device, a detection connection means is provided, and the detection connection means Since the operating voltage further inside the current input terminal of the electronic device is detected, the actual operating voltage of the electronic device can be detected and the operating voltage can be held constant. This allows the electronic device to operate stably, which is particularly advantageous when applied to electronic devices that operate intermittently and have large load fluctuations, such as electronic still cameras.

Further, since it is not necessary to supply a voltage larger than necessary in consideration of voltage drop, the capacity of the power supply circuit can be small, and miniaturization is possible. Furthermore, heat dissipation measures are also unnecessary.

As a result, there is no difference in voltage from when using a secondary battery, and the operation of the motor, solenoid, etc. becomes stable.

Furthermore, even if the resistance of the cable that supplies current or the connector itself increases, the effect can be suppressed, so that the cable can be made thinner, longer, and lighter overall.

Further, according to the power supply device according to claim 2 of the present invention,
Since the operating voltage of the current input terminal of the electronic device is detected by the detection connection means, the operating voltage of the electronic device can be detected without being affected by the resistance of the connection means that supplies the operating current to the electronic device. can be controlled.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of an embodiment of the power supply device of the present invention, FIG. 2 is a block diagram showing the structure of an example of a conventional power supply device, and FIG. 3 is a block diagram showing the structure of an example of a conventional AC adapter. FIG. 4 is a waveform diagram explaining the operation in the example of FIG. 2; FIG. 5 is a waveform diagram explaining the operation in the example of FIG. 1; FIG. FIG. 3 is a block diagram showing the structure of another embodiment of the power supply device of FIG. Engineering... AC adapter 7... Output terminal 10... Comparison circuit section 11... Reference voltage generation circuit engineering 4... Output terminal 2l... Electronic still camera 22... Input terminal 23...・Protective circuit 29...Input terminal 31.32...Cable 41.42...Terminal 61.62...Cable 19-

Claims (2)

[Claims] (1) A power supply device that rectifies and smoothes an alternating current voltage to generate a constant direct current voltage and supplies this to electronic equipment, the power supply having a first output terminal that outputs the direct current voltage, and a second output terminal that is grounded. an output terminal; a first connection means for connecting the first input terminal to which a DC voltage of the electronic device is input; and the first output terminal; and a grounded second input of the electronic device. a second connection means for connecting the terminal and the second output terminal; a first detection input terminal to which a detection signal for detecting the working voltage of the electronic device is input; and a grounding means for the electronic device. a second detection input terminal into which a detection signal for detecting voltage is input; the first detection input terminal; and a first detection output terminal connected to a detection point for detecting the operating voltage of the electronic device. and fourth connection means for connecting the second detection input terminal and a second detection output terminal connected to a detection point for detecting the ground voltage of the electronic device. and a comparison circuit that compares the voltage between the first detection input terminal and the second detection input terminal with a reference value, and controls the DC voltage according to the comparison result. (2) A power supply device that rectifies and smoothes an alternating current voltage to generate a constant direct current voltage and supplies this to electronic equipment, the power supply having a first output terminal that outputs the direct current voltage, and a second output terminal that is grounded. an output terminal; a first connection means for connecting the first input terminal to which a DC voltage of the electronic device is input; and the first output terminal; and a grounded second input of the electronic device. a second connection means for connecting the terminal and the second output terminal; a first detection input terminal to which a detection signal for detecting the working voltage of the electronic device is input; and a grounding means for the electronic device. a second detection input terminal into which a detection signal for detecting voltage is input; third connection means for connecting the first detection input terminal and the first input terminal of the electronic device; a fourth connection means for connecting the second detection input terminal and the second input terminal of the electronic device; and a voltage between the first detection input terminal and the second detection input terminal as a reference. A power supply device comprising a comparison circuit that compares the DC voltage with the DC voltage and controls the DC voltage according to the comparison result.