JPH0265478A - Power supply system - Google Patents

Abstract

PURPOSE:To operate a drive section stably independently of a power voltage level fed from a power supply section to the 2nd device by providing a means correcting a control signal supplied from the 1st device in response to the voltage level of the power supply supplied from the power supply section to the 2nd device. CONSTITUTION:A power supply is supplied to a terminal 104 or a lens unit from a camera main body and fed to a control section 107 via an A/D converter 108. Then the drive speed of a motor 101 receiving a power voltage such as 5V is used as a reference. The control section 107 controls the duty of the switch control pulse controlling a switch 103 in response to the output data of the A/D converter 108 being information of the power voltage supplied to the terminal 104 while being fluctuated around the 5V. Thus, the motor 101 is driven at a constant speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply system that supplies power from a device equipped with a power supply unit to an external device connectable to the device.

[Conventional technology]

In a conventional video camera system in which a lens unit with a built-in motor and the like and a camera main body are detachable and replaceable, the lens unit receives control data and the lens unit from a control section of the camera main body. In order to drive the built-in motor, etc., power is supplied from a power supply section included in the camera body.

FIG. 2 is a diagram showing a schematic configuration of the above-mentioned video camera system. In FIG. 2, the lens unit 201 is
It has a mechanism part 202, a motor 203 that moves this, and a motor drive circuit 204 that drives this motor,
The motor drive circuit 204 is supplied with control data and power from a control section 208 and a power supply section 209, respectively, through a terminal 205 and a terminal 207 connected to the camera section main body 206 side. FIG. 3(a) shows an example of the configuration of the motor drive circuit 204. The motor 301 includes a switch 303 controlled by drive data 302.
A power source 304 is connected via the power source 304 . The drive data is, for example, a pulse as shown in FIG. 3(b), and this drive data is the control data 3 input from the camera body.
05 is data-processed by the control unit 306. The switch 303 is controlled so that it is in an ON state while the drive data 302 is at a high level, and is in an OFF state when it is at a low level. Then, the motor 301 is driven at a speed according to the duty of the drive data 302.

[Problems to be Solved by the Invention] However, in the conventional system as described above, the lens unit 201 uses control data 306 sent from the camera body 206 to which it is attached.
Even if the data is the same, if the voltage of the power supplied from the power supply section 209 in the camera section main body 206 is different, the driving speed of the motor 203 will change according to the power supply voltage.

The present invention eliminates the drawbacks of the conventional devices as described above, and also makes it possible to cause the external device to perform a predetermined operation even when the external device is connected to devices supplied with different power supply voltages. The purpose is to provide a power supply system that can.

[Means to solve the problem]

The power supply system of the present invention is a system that supplies power from a first device equipped with an N source to a second device connectable to the first device, and operates the second device. hand,
an N source unit that generates power supplied from the first device to the second device; and a drive that is provided in the second device and operates based on a control signal supplied from the first device. and a correction means for correcting the control signal supplied from the first device according to the voltage level of the power supply supplied from the power supply section.

[For production]

With the above-described configuration, the drive section can be operated stably regardless of the power supply voltage level supplied from the power supply section to the second device.

〔Example〕

Hereinafter, the present invention will be explained using one embodiment of the present invention.

FIG. 1 is a diagram showing a schematic configuration of a motor drive circuit within a lens unit in a video camera system as an embodiment of the present invention. In FIG. 1, the terminal 106 is supplied with 111B data from the control section of the camera body (not shown) to which the lens unit is attached, and the terminal 104 is supplied with power from the power supply section of the camera body. . 7! supplied to terminal 104! & source has a voltage value of A/
It is converted into voltage data by the D converter 108 and sent to the control unit 1.
07. The A/D converter 108 is an A/D converter that converts an input signal into 8-bit data, for example, and here, when an input signal of 5 [V] is input, the digital output is 7H'' in hexadecimal. In addition, when the power supply voltage input to the motor 101 is 5 [V], the high level and low level duty of the switch 103 that determines the rotation speed of the motor 101 is set. 20/80, and the rotational speed of the motor 101 at this time is used as a reference.

The control unit 107 controls the motor 101 by controlling the duty of the switch control pulse that controls the switch 103 in accordance with the output data of the A/D converter 108, which is information on the power supply voltage supplied to the terminal 104. It becomes possible to rotate at a constant rotation speed.

FIG. 4 shows a correspondence table between the voltage data output from the A/D converter 108 and the duty of the switch control pulse. As shown in FIG. 4, the voltage of the power supply supplied to the terminal 104 is high, and the voltage data of the A/D converter lO8 is “F”.
When the voltage becomes H", the duty is set to 10790, and when the voltage of the power supply is low and the voltage data of the A/D converter 108 becomes #3.4", the duty is set to 4.0/
60, such a duty switch control pulse is generated from the control unit 107, the switch 103 is controlled by this switch control pulse, and the power supplied to the terminal 104 is supplied to the motor 101. can be rotated at a constant rotation speed.

FIG. 5 is a diagram showing a schematic configuration of a motor drive circuit in a lens unit in a video camera system 1 as another embodiment.

In FIG. 5, power is supplied to a motor 510 from a power supply section of a camera main body (not shown) to which a lens unit is attached to a terminal 501, and a transistor 502 installed between the motor 510 and the ground supplies power to the motor 510.
The current flowing through 10 is controlled.

Further, control data corresponding to the drive amount of the motor 510 from the control unit of the camera body is inputted from the terminal 503 to the control unit 504, and the control unit 504 outputs voltage data according to the control data. Converter 505 is provided.

Then, the D/A converter 505 converts the supplied voltage data into an analog voltage signal, and the mixing amplifier 505 converts the supplied voltage data into an analog voltage signal.
6 to the base of the transistor 502.

On the other hand, the voltage of the power supply supplied to the motor 510 from the terminal 501 is compared with the reference voltage Vref output from the reference voltage source 507 in the comparator 508, and a differential voltage signal corresponding to the difference is sent to the negative terminal of the mixing amplifier 506. is supplied to

Therefore, a voltage signal corrected according to the voltage level of the power supply supplied to the terminal 501 is supplied from the mixing amplifier 506 to the base of the transistor 502, and is supplied to the base of the transistor 502. A current corresponding to the level of the voltage signal is supplied to the motor 510.

For example, if the voltage of the power supply supplied to the terminal 501 is higher than the reference voltage source Vref output from the reference voltage source 507, the output of the comparator 508 is supplied to the negative terminal of the mixing amplifier 506, so The output of the mixing amplifier 506 is lowered by the output voltage of the comparator 508, and when it is lower than the reference voltage source Vref, the output of the mixing amplifier 506 is lowered by the output voltage of the comparator 508.
By supplying the output voltage signal of the mixing amplifier 506 corrected in this way to the base of the transistor 502, the output voltage of the motor 5 is increased by the output voltage of the motor 5.
The current flowing through the motor 10 is constant, and the rotational speed of the motor 510 is kept constant regardless of the voltage of the supplied power source.

As explained above, in a video camera system where the lens unit and the camera body are removable and replaceable, even if there are variations in the power supply voltage supplied from the camera body to the lens unit, the It becomes possible to rotate at a constant rotation speed without changing the rotation speed of the motor.

Although the present embodiment has been described using a video camera system as an example, the present invention can be applied to other devices as well.

〔Effect of the invention〕

As explained above, according to the present invention, even when an external device is connected to devices supplied with different power supply voltages, it is possible to cause the external device to perform a predetermined operation. We can provide a reliable power supply and supply system.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a motor drive circuit within a lens unit in a video camera system as an embodiment of the present invention. FIG. 2 is a diagram showing a schematic configuration of a conventional video camera system. FIG. 3(a) is a diagram showing an example of the configuration of the motor drive circuit 204 shown in FIG. 2. FIG. FIG. 3(b) is a diagram showing a pulse waveform of drive data output from the control section 306 shown in FIG. 3(a). FIG. 4 is a diagram showing the relationship between the value of voltage data output from the A/D converter 108 in FIG. 1 and the duty of switch control data output from the control section 107. FIG. 5 is a schematic configuration diagram of a motor drive circuit in a lens unit in a video camera system as another embodiment of the present invention.

Claims (1)

[Scope of Claims] A system for supplying power from a first device including a power supply unit to a second device connectable to the first device to operate the second device, comprising: a power supply section that generates power supplied from the first device to the second device; a drive section that is provided in the second device and operates based on a control signal supplied from the first device; A power supply system comprising: a correction means for correcting a control signal supplied from the first device according to a voltage level of the power supply supplied from the power supply unit.