JP2008118517A - Television camera apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact television camera apparatus which has low power consumption with small heat generation and is suitable to realize a very compact television camera apparatus. <P>SOLUTION: In a very compact television camera apparatus, input power supply voltage 1 is boosted by about 1.2 times or more with a charge pump boosting circuit 2 to make the supply voltage 1 almost equivalent to the reference voltage of an video signal processing circuit. Based on that voltage, the reference voltage of the video signal processing circuit is produced to operate the video signal processing circuit of the camera. Power supply voltages for driving a CCD and the like are produced by further boosting the output voltage of the charge pump boosting circuit 2 two times with a double charge pump boosting circuit 3, and by inverting the output voltage with a charge pump inverting circuit 4. Thereby, power supply circuits suitable for a compact television camera apparatus having low noise and small heat generation can be realized. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

    The present invention relates to an improvement of a power supply circuit configuration in an ultra-small television camera device.

FIG. 3 shows an overall configuration diagram of a conventional television camera apparatus. In this figure, the power supply voltage inside the camera is created by converting the input voltage with a switching power supply circuit such as a DC / D converter. The main power supply voltage input to the camera from outside is + 12V, but the power supply voltage required inside the camera is +12 to + 15V, -5 to -7V for CCD drive, and + 5V for signal processing. Since several types such as + 3.3V are required, a switching power supply circuit as shown in FIG. 4 has been used. When there is a switching power supply circuit inside the camera, the switching power supply circuit turns on / off the line of the input power supply voltage using an FET (field effect transistor) or a normal transistor. A current flows, which easily affects the video signal processing circuit, which is one of the causes of image quality degradation. In particular, in an ultra-small television camera device, it is one of the factors that hinder the improvement of image quality because it is easily affected by the small mounting area of components.

Examples of patents already filed using a switching power supply circuit in a television camera device include the following.
JP 10-224663 A

As described above, the switching power supply circuit is used for the power supply circuit of the conventional camera. However, in the ultra-small television camera device, the mounting area of the parts is small and the wiring is close, so that the switching power supply circuit The switching noise generated when the FET or transistor is turned on / off greatly affects the image quality of the camera. In addition, in order to prioritize image quality, when a series regulator is frequently used without using a switching power supply circuit, the potential difference between the input and output of the series regulator becomes a loss as it is and heat generation increases. When the housing of the television camera is small, this causes a problem in practice because the area for releasing the heat is small. Also, a series regulator alone cannot produce all the voltages needed inside a television camera.

The present invention generates the voltage required inside the television camera by solving the above-mentioned problems that the power supply circuit of the conventional ultra-small television camera device has, and there is no image quality deterioration of the display image. An object of the present invention is to provide a television camera device that generates little heat.

  In order to achieve the above object, in the present invention, in a portable television camera device, a plurality of DC power supply voltages required for a television camera are converted into a charge pump booster circuit and a series regulator that removes ripples of the output voltage. (Claim 1).

At this time, the charge pump booster circuit is generated by combining a normal charge pump booster circuit, a double charge pump booster circuit, and a charge pump inverter circuit that generates a negative power supply voltage. (Claim 2).

Actually, it is output from the input power supply voltage, the charge pump booster circuit 2 that boosts the input power supply voltage, the series regulator 5 that removes the ripple of the voltage output from the charge pump booster circuit 2, and the charge pump booster circuit 2. Output from the double charge pump type booster circuit 3 that further boosts the voltage twice, the charge pump type inverter circuit 4 that generates the negative power supply voltage, the double charge pump type booster circuit 3 and the charge pump type inverter circuit 4. A series regulator 5 for removing voltage ripple and generating a driving voltage for the CCD is provided.

Further, the voltage output by the charge pump type booster circuit 2 is set to about 1.2 times the input power supply voltage, and the double charge pump type booster circuit 3 further boosts the voltage to twice the charge pump type inverter circuit 4. Then, the output voltage of the charge pump type booster circuit 2 is inverted (claim 4).

In the television camera apparatus, in order to generate a voltage used inside the camera, the input power supply voltage is made substantially equal to the video signal processing circuit reference power supply voltage, and the boosting of the power supply voltage and the negative power supply voltage are a charge pump type booster circuit, 2 Since it is generated by using the double charge pump type booster circuit and charge pump type inverter circuit, it can suppress heat generation due to power loss and power noise, so it can be used with low power consumption even in an ultra-small housing. A small television camera device that generates less heat can be manufactured.

  An embodiment of the present invention will be described with reference to FIG. In this figure, the series regulator 5 is a circuit that removes ripple noise in the input voltage and outputs a stable voltage, and is the same as the prior art shown in FIG. The circuit up to now will be described.

An input power supply voltage 1 substantially equal to the video signal processing circuit reference power supply voltage is first boosted by the charge pump booster circuit 2. In this step-up, if 6V which is about ½ of the power supply voltage for driving the CCD + 12V is generated, the subsequent loss can be further reduced. The video signal processing circuit reference power supply voltage can be stably obtained by stabilizing the voltage obtained by the charge pump type booster circuit 2 by the series regulator 5, even if the input voltage fluctuates somewhat. In order to drive the CCD, a higher power supply voltage such as + 12V and a negative power supply voltage such as -5V are required. Among the voltages for driving the CCD, + 12V can be obtained by further doubling the voltage output by the charge pump type booster circuit 2 by the double charge pump type booster circuit 3. Further, a negative voltage such as −5 V can be obtained by inverting the output voltage of the charge pump type booster circuit 2 by the charge pump type inverting circuit 4. The voltage output from the double charge pump type booster circuit 3 and the charge pump type inverter circuit 4 can be further stabilized by removing ripple noise and the like by using the series regulator 5. In order to reduce heat generation as a camera, the voltage between the input and output of the series regulator 5 needs to be minimized. Therefore, the capacitance of the capacitor in the charge pump type booster circuit 2 is trimmed so as to be the voltage. Thus, the output voltage of the charge pump type booster circuit 2 may be determined.

An actual circuit example of the charge pump type booster circuit used in the apparatus of the present invention is shown in FIG. In this circuit, the input voltage input to IN is boosted by a charge pump type booster circuit composed of a P-channel FET 21, an N-channel FET 22, a diode 23, and a capacitor 24. The circuit example of the double charge pump booster circuit is realized by using two P-channel FETs 31 and two N-channel FETs 32 as shown in FIG. The charge pump type inverting circuit can be realized by a circuit as shown in (c).
Each FET in each circuit controls the charging of the capacitor at the latter stage of the FET, so the power supply line is not turned ON / OFF directly like the switching circuit shown in FIG. There is no switching noise generated at the time of / OFF, and there is no large loss as in the case of using a series regulator circuit, so there is little heat generation. The noise that affects the video signal when using a charge pump type circuit with our camera of the same type can be reduced to 1/10 compared with the case of using a switching power supply circuit, and the efficiency of the power supply circuit is 20%. Percentage could be improved. In addition, since the charge pump type circuit does not use an expensive dedicated IC used in a switching power supply circuit, the cost of the power supply circuit can be reduced by 20%.

As a television camera device with little image deterioration, it can be used in a wide range of fields. In particular, it is ideal for applications such as image inspection of wire bonding state mounted on the tip movable device part of a wire bonder used for semiconductor wiring on a printed circuit board, image shooting by attaching to a microscope, and use as a small security camera. is there.

Block diagram of power supply for television camera apparatus of the present invention FIG. 4 is a diagram showing an example of a charge pump type booster circuit. (A) A diagram showing an example of a charge pump type booster circuit. (B) A diagram showing an example of a double charge pump type booster circuit. (C) An example of a charge pump type inverter circuit. Figure Block diagram of a conventional power supply for a television camera device The figure which shows the example of the conventional switching type power supply circuit

Explanation of symbols

1: input power supply 2: charge pump booster circuit 3: double charge pump booster circuit 4: charge pump inverter circuit 5: series regulator 9: switching power supply circuit 21, 31, 41, 91: P channel FET (field effect) Transistor)
22, 32, 42: N-channel FET
23, 33, 43, 93: Diodes 24, 34, 44, 94: Capacitor 35: Inverter 92: Coil 95: Switching power supply control IC

Claims (4)

A portable television camera device, wherein a plurality of DC power supply voltages required for a television camera are generated by combining a charge pump booster circuit and a series regulator that removes ripple of the output voltage. apparatus. 2. The television camera apparatus according to claim 1, wherein a normal charge pump booster circuit, a double charge pump booster circuit, and a charge pump inverter circuit that generates a negative power supply voltage are used as the charge pump booster circuit. A television camera device characterized by being generated in combination. 3. The television camera device according to claim 1, wherein the input power supply voltage, the charge pump booster circuit 2 that boosts the input power supply voltage, the series regulator 5 that removes the ripple of the voltage output from the charge pump booster circuit 2, and the charge pump. Double charge pump booster circuit 3 that further boosts the voltage output from booster circuit 2, charge pump inverter circuit 4 that generates a negative power supply voltage, double charge pump booster circuit 3, and charge pump A television camera apparatus having a series regulator 5 for removing a ripple of a voltage output from a mold inversion circuit 4 and generating a driving voltage for a CCD. 4. The television camera device according to claim 1, wherein the voltage output from the charge pump type booster circuit 2 is about 1.2 times the input power supply voltage, and the double charge pump type booster circuit 3 further includes a voltage. The charge pump type inverter circuit 4 inverts the output voltage of the charge pump type booster circuit 2, thereby minimizing internal power loss and reducing the size of the housing to a very small size. A television camera device characterized by low heat generation.

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