JPH04222902A - Rotary type power supply - Google Patents

Abstract

PURPOSE:To transmit different driving voltage in non-contact to a load provided in the secondary side of a rotary transformer without changing the constitution of rotary transformer. CONSTITUTION:At the time of recording mode, a control means 34 is changed over to the solid line side by a control signal Sc and a switching signal Sb is supplied to a 2nd switching element 26, and at the same time a switching signal Sa is supplied to a 1st switching element 22. Then, both 1st and 2nd switching elements 22,26 are complementarily operated, and an amplitude voltage Va, approximately twice of an input power source voltage Vcc, is impressed on both terminals of a primary winding La and transmitted to the side of secondary winding Lb. At the time of reproducing mode, the changeover is made to the broken line side and an inverter 20 becomes the half bridge operating state since a constant voltage is always supplied to the 1st switching element 26, then the amplitude voltage Va becomes approximately equal to the input power source voltage Vcc, which is transmitted to the side of secondary winding Lb.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention relates to a V having a rotating drum.
The present invention relates to a rotary power supply device suitable for application to a rotating magnetic head device of a TR, etc., and is capable of selectively supplying several types of driving voltages required particularly on the rotating drum side with a simple configuration.

0002

2. Description of the Related Art In a rotating magnetic head device used in a VTR, the rotating drum is composed of a pair of upper and lower drums, and only the upper drum side to which the rotating magnetic head is attached is rotatable. There is. In addition to a rotating magnetic head, the upper drum side is often equipped with a recording and reproducing amplifier.

In order to drive these recording or reproducing amplifiers, it is necessary to supply them with a driving voltage, but since these are provided on the rotating upper drum side, a rotating transformer is used as the power supply means. Requires a non-contact power supply (rotary power supply). This rotating transformer for power supply is provided separately from the rotating transformer for transmitting and receiving signals.

FIG. 3 shows a conceptual diagram of a rotary power supply device 10 used in such a rotary magnetic head device. In the same figure, a DC power source 12 is supplied as an input power source to an inverter 20, and this power source voltage Vcc has a predetermined frequency (for example, 20 KHz).
The chopped power supply voltage is chopped (DC-AC inverted) by the rotating transformer PR for power supply.
It is applied to both ends of the primary winding La of T.

[0005] All parts after the secondary side of the rotary transformer PRT are provided on the upper drum side. Therefore, the rotating transformer PRT
The drive voltage (secondary side drive voltage) transmitted non-contact to the secondary winding Lb of is rectified and smoothed by a full-wave rectifier circuit (including smoothing) 14. The secondary drive voltage is further converted into a predetermined drive voltage by the regulator 16, and this converted drive voltage is applied to the load 18. The load 18 is a recording amplifier and a reproduction amplifier as described above.

FIG. 4 shows a specific example of the full-wave rectifier circuit 14, regulator 16, and load 18 provided on the upper drum side. In the figure, 18R is a recording amplifier, to which a recording head (not shown) is connected. 18P is a playback amplifier, to which a playback head (not shown) is connected. The recording amplifier 18R operates with a drive voltage of about -11 volts, whereas the playback amplifier 18P
operates with a driving voltage of about -5 volts.

Therefore, as shown in the figure, separate regulators 16A and 16B are provided, and a stabilized driving voltage of -5 volts is applied from regulator 16B to regenerative amplifier 18P. Further, a stabilized voltage of -11 volts is applied from the other regulator 16A to the recording amplifier 18R. In this regulator 16B, the voltage at the connection point p is -
When the voltage is 14 volts, a voltage of -11 volts is output, but when a voltage of -11 volts or less is applied, the input voltage is output as is. C is a smoothing capacitor.

[0008]

[Problem to be Solved by the Invention] By the way, when there are two or more types of drive voltages required on the load side, it may be configured to apply the corresponding drive voltages depending on the operating mode. . This is because when the playback mode is selected, only the playback amplifier 18P is operated, and when the write-after-read mode is selected, both the recording amplifier 18R and the playback amplifier 18P are operated.

Conventionally, a voltage of about -14 volts is always applied to the connection point p regardless of the operating mode, so that both the recording amplifier 18R and the reproducing amplifier 18P are always in operation. When configured to change the driving voltage depending on the operation mode, 1. It controls the regulator 16 provided on the upper drum side. 2. Change the transformation ratio of the rotating transformer PRT. This is because measures such as these must be taken.

However, it would be possible to selectively supply the required drive voltage to the upper drum without changing the size or shape of the rotary transformer PRT or without sending regulator control signals to the upper drum. , it is clear that such a configuration is better.

[0011] Therefore, the present invention solves these conventional problems, and in particular, provides a method that allows a plurality of drive voltages to be selectively supplied to the upper drum side with a simple structure and without increasing costs. This paper proposes a rotary power supply device with the following features.

0012

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a rotary power supply device that supplies a predetermined drive voltage to the rotating drum side via a rotary transformer. A DC-AC inverter is provided on the primary winding side of the transformer, and this inverter has first and second switching elements provided at both ends of the primary winding, and each of these switching elements is connected to a predetermined power supply voltage. Switching signals having an opposite phase relationship with each other are supplied, and switching control means is provided to either the first or second switching element, and the switching control means causes the first or second switching element to The device is characterized in that either the power supply voltage or a voltage higher than the power supply voltage is applied to both ends of the primary winding by controlling the operating state of the switching element.

[0013]

[Operation] By controlling the control means 34 provided in the DC-AC inverter 20, the output voltage Va of the inverter 20 is controlled. In FIG. 1, the control means 34
When the control switch functioning as
is supplied to the first switching element 22, and a switching signal Sb having an opposite phase to the switching signal Sa is supplied to the second switching element 26. Therefore, this inverter 20 operates as a full bridge type inverter.

Therefore, in this state, the rotating transformer P
The amplitude voltage Va at both ends of the primary winding La of the RT is the DC power supply (
Input power supply) Voltage 2V, almost twice the power supply voltage Vcc of 12
cc. As a result, this voltage 2Vcc (=Va) is induced in the secondary winding Lb (the winding ratio with the primary winding La is 1:1) of the rotary transformer PRT.

On the other hand, when the control means 34, which is a control switch, is switched as shown by the broken line, the DC voltage Vcc
is applied to the second switching element 26, so in this example, the other switching element 26b is always on, and the inverter 20 operates as a half-bridge type inverter. As a result, the amplitude voltage V at both ends of the primary winding La
a becomes approximately the input voltage Vcc, and a voltage corresponding to the input voltage Vcc is induced in its secondary winding Lb.

That is, since the voltage itself transmitted to the upper drum side is controlled by controlling the inverter 20, the winding ratio of the rotary transformer PRT and the input power supply voltage V
By appropriately setting the value of cc, different driving voltages required by the load 18 can be selectively supplied.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an example of a rotary power supply device according to the present invention applied to the above-mentioned rotary magnetic head device of a VTR will be described in detail with reference to FIG. 1 and subsequent figures.

The present invention is also based on the rotary power supply device 10 as shown in FIG. 3, and the loads 18 are the recording amplifier 18R and the reproduction amplifier 18P as described above. Recording amplifier 18R is -11
It is assumed that the reproducing amplifier 18P operates with a drive voltage of -5 volts.

In the present invention, the DC-AC inverter 20 is provided with the following means. FIG. 1 shows a diagram of the principle of this invention, and the inverter 20 used is a full bridge type. This inverter 20 has first and second switching elements 22 and 26 complementary connected to the primary winding La side of the rotary transformer PRT via DC cut capacitors 24 and 28, respectively.

[0020] The first and second switching elements 22,
26 itself is also a pair of complementary connected switching elements (22a, 22b), (26a, 26
b). As the switching elements 22 and 26, MOS/FETs are used as shown in the figure. A predetermined power supply voltage Vcc is applied from the DC power supply 12 to the pair of switching elements 22 and 26.

A switching signal (rectangular wave signal) Sa of a predetermined frequency (for example, 20 KHz) is supplied from a signal source 30 to the gate of the first switching element 22, and a switching signal Sa is supplied to the gate of the second switching element 26.
The switching signal Sb, which has an opposite phase relationship with the signal source 32
More selectively supplied. Second switching element 26
A control means 34 is provided between the signal source 32 and the signal source 32 for selectively supplying the switching signal Sb.

In principle, a control switch is used as the control means 34, and the control signal Sc supplied from the terminal 36
The switching is controlled as shown by the solid line or the broken line. Therefore, when controlled as shown by the solid line, the switching signal Sb is supplied to the second switching element 26, and when controlled as shown by the broken line, the power supply voltage Vcc is applied instead of the switching signal Sb. It is configured.

As shown in the figure, the control signal Sc is a binary signal that changes to low level in the recording mode, and when the control signal Sc is at low level, it is switched as shown by the solid line, and the inverter 20 is switched to the original full bridge type. It works. Therefore, at this time, both the first and second switching elements 22 and 26 perform a switching operation, and in the negative half cycle of the switching signal Sa, the switching element 22a
- primary winding La - a current path of the switching element 26b is formed, in the positive half cycle the switching element 26
A - Primary winding La - A current path of switching element 22b is formed, resulting in complementary operation, and primary winding L
The amplitude voltage Va at both ends of a becomes a voltage 2Vcc, which is approximately twice the input power supply voltage Vcc.

This voltage Va is transmitted to the secondary winding Lb of the rotary transformer PRT. In this example, the winding ratio of the rotary transformer PRT is 1:1. Therefore, the voltage Vb (=Va) transmitted to the secondary side is rectified and smoothed by the rectifier circuit 14, and this rectified and smoothed output voltage Vb
is further supplied to the regulator 16 to provide a predetermined drive voltage Vp.

In the case of the configuration shown in FIG. 4, the voltage Vp (=2Vcc) at point p is approximately -14 volts, and this voltage Vp is applied to the regulators 18R and 18P.
The signal is applied to the recording amplifier 18R and the reproduction amplifier 18P, which serve as loads, through the amplifier.

On the other hand, the high level control signal Sc
When is supplied, the control switch 34 is switched as shown by the broken line, and the input power supply voltage Vcc is always applied to the second switching element 26, so that one switching element 26b is controlled to be always on. . Therefore, one end of the primary winding La is grounded, only the first switching element 22 is switched by the switching signal Sa, and the input power supply voltage Vcc is applied to the primary winding La only for half a cycle of the switching signal Sa. . That is, in this case, the inverter 20 operates as a half-bridge type inverter.

As a result, the amplitude voltage V across the primary winding La
Since a is approximately the input power supply voltage Vcc, this voltage Va
is transmitted to the secondary winding Lb side of the rotating transformer PRT, where it is rectified and smoothed. Therefore, the voltage Vp at point p becomes approximately -Vcc, and the regulator 16B outputs a driving voltage (-5 volts) sufficient to drive only the reproduction amplifier 18P.

FIG. 2 is a specific example of FIG. 1, in which the control means 3
4, a two-input type OR gate is used, one of which is supplied with the switching signal Sb, and the other of which is supplied with the terminal 36.
A control signal Sc is supplied from. Note that, in order to maintain the symmetry of the circuit, an OR gate 40 is also connected to the first switching element 22 side. However, their input sides are commonly wired. 42, 44 are switching elements 22a, 22b,
This is a driver for driving 26a and 26b.

In this configuration, when the low level control signal Sc is supplied to the terminal 36 in the recording mode, the switching signal Sb is directly transmitted to the second switching element 2.
2. As a result, the inverter 20 operates as a full bridge type inverter, and a voltage of 2 Vcc is induced on the secondary side of the rotary transformer PRT. On the other hand, when a high-level control signal Sc is supplied to the terminal 36 in the reproduction mode, the output of the OR gate 34 is logic "1" and the switching element 26b is always on, so in this case, half It operates as a bridge type inverter 20, and a voltage of Vcc is induced on the secondary side of the rotating transformer PRT.

In FIG. 2, 46 and 48 are commutating diodes. When using MOS/FET as the switching elements 22b, 26b, the switching element 2 is used as the commutating diodes 46, 48.
Since the parasitic diode parasitic between the drain and source of 6a and 26b can be used, there is no need to provide another diode for commutation.

Although the present invention has been applied to a rotating magnetic head device in the above description, the present invention can also be applied to other cases where it is necessary to supply a predetermined power supply voltage in a non-contact manner. The control means 34 may be provided on the first switching element 22 side.

[0032]

As described above, in the rotary power supply device according to the present invention, different voltages can be induced on the secondary side of the rotary transformer by controlling the operating mode of the inverter.

The configuration is also simple, with a control means consisting of a control switch and a single logic circuit, and there is no need to use switching elements that require particularly high voltage resistance, and there is no need for a rotating transformer. Since the conventional structure can be used, a rotary power supply device can be realized without increasing the cost.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing the principle configuration of a rotary power supply device according to the present invention.

FIG. 2 is a connection diagram showing a specific example of FIG. 1;

FIG. 3 is a system diagram showing an example of a rotary power supply device.

FIG. 4 is a system diagram showing a specific example of a part of FIG. 3;

[Explanation of symbols]

10 Rotary power supply device 12 Input power supply 14 Full wave rectifier circuit 16 Regulator 16A regulator 16B regulator 18 Load 18A recording amplifier 18B playback amplifier 20 DC-AC inverter 22 First switching element 22a Switching element 22b Switching element 26 Second switching element 26a Switching element 26b Switching element 30 Signal source 32 Signal source 34 Control means PRT rotary transformer La Primary winding Lb Secondary winding Sa Switching signal Sb switching signal Sc control signal

Claims (1)

[Claims] 1. A rotary power supply device configured to supply a predetermined drive voltage to a rotating drum side via a rotary transformer, wherein a DC-A power supply is provided on the primary winding side of the rotary transformer.
A C inverter is provided, and this inverter has first and second switching elements provided at both ends of the primary winding, and each of these switching elements receives a predetermined power supply voltage and a switching signal having an opposite phase relationship with each other. is supplied, and the first or second
A switching control means is provided in any one of the switching elements, and the switching control means controls the first switching element.
Alternatively, a rotary type characterized in that either the power supply voltage or a voltage higher than the power supply voltage is applied to both ends of the primary winding by controlling the operating state of the second switching element. Power supply device.