JPH073446Y2 - Magnetic recording circuit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnetic recording circuit for magnetically recording on a magnetic recording medium such as a floppy disk.

[Conventional technology]

As shown in FIG. 2, the magnetic recording circuit magnetizes and drives the coil 2 of the magnetic head according to the data to be written on the magnetic recording medium. A drive power source (V _CC ) is connected to the center tap of the coil 2. , The switching elements 8 and 10 are connected to both ends of the coil 2 via damping resistors 4 and 6, and the constant current source 16 for flowing the write current I _WR is connected via the switching elements 12 and 14. ing.

Usually, two sets of magnetic recording circuits are installed corresponding to the recording surface of a floppy disk. Therefore, the switching elements 8 and 10 select the operation of the magnetic recording circuit on the writing side, and are closed during driving. Since the magnetic heads are installed close to each other, the magnetic field generated in the coil on the selection side may act on the coil on the non-selection side to generate an induced current during reading. Therefore, the switching elements 8 and 10 are opened. By disconnecting the damping resistors 4 and 6 from each other, generation of an induced current in the coil on the non-driving side is suppressed, and unnecessary interference is prevented.

For example, the coil 2 is selected and the switching element 8,
10 is closed, switching element according to write data
When 12 and 14 are alternately opened and closed, the coil 2 is magnetized by the write current I _WR flowing from the constant current source 16, and a magnetizing voltage is generated between the terminals of the coil 2.

[Problems to be solved by the invention]

By the way, in such a magnetic recording circuit, a DC current I _d flows from the power supply side through the coil 2 to the damping resistors 4 and 6 during driving, resulting in power consumption. Damping resistor 4,
Since 6 to 5 kΩ is used, the power supply voltage
When V _CC is 5V, DC current I _d is 10 ~ 2mA, power consumption P _W is
If the power supply voltage V _CC is 12V,
The direct current I _d is 24 to 4.8 mA, and the power consumption P _W is 288 to 58 mW. Such power consumption is extremely uneconomical, and especially when a battery is used as a driving power source, it becomes a cause of hastening its consumption.

Therefore, this invention is intended to reduce the power consumption of the magnetic recording circuit.

[Means for solving problems]

As shown in FIG. 1, the magnetic recording circuit of this invention has damping resistors 4A, 6 at both ends of coils 2A, 2B of a magnetic head.
A first switching element (transistor 30A, 32A, 30B, 32B) that is closed during operation is installed via A, 4B, 6B and capacitors 22A, 24A, 22B, 24B, and a second switching element is installed.
Switching elements (transistors 34A, 36A, 34B, 36
Magnetizing current (writing current I _WR ) to coils 2A and 2B via B)
A current source (constant current source 40) for flowing the current is installed.

[Action]

Capacitor 22 for damping resistors 4A, 6A, 4B, 6B
Since A, 24A, 22B, and 24B are connected in series, the flow of direct current is blocked, and the generation of power consumption by the damping resistors 4A, 6A, 4B, and 6B is prevented. And damping resistance
Even if the capacitors 22A, 24A, 22B, and 24B are connected in series to the 4A, 6A, 4B, and 6B, the function as the damping resistor is as follows:
Charged by impedance by B and 24B.

〔Example〕

 FIG. 1 shows an embodiment of the magnetic recording circuit of the present invention.

The coils 2A and 2B are installed in two magnetic heads corresponding to the recording surface of a recording medium such as a floppy disk.

The coil 2A is connected to the drive terminals 18A and 20A for supplying the write current I _WR as a magnetizing current, and also to the operation selection terminals 26A and 28A via the damping resistors 4A and 6A and the capacitors 22A and 24A. Connected and also coil 2B
Is connected to the drive terminals 18B and 20B for passing the write current I _WR, and is also connected to the operation selection terminals 26B and 28B via the damping resistors 4B and 6B and the capacitors 22B and 24B, and the respective coils 2A. , 2B have operation selection terminals 26A, 2
Transistors 30A, 32A, 30B and 32B as first switching elements, which are closed during operation, are individually connected via 8A, 26B and 28B.

In addition, the coil 2A responds to the operation of the transistors 34A and 36A as the second switching elements, and the coil 2B similarly operates as the second switching element.
According to the operation of 34B and 36B, the write current I _WR generated in the constant current source 40 is supplied through the current mirror circuit including the transistors 42 and 44 and the resistors 46 and 48. Transistor
The transistor 34A and the transistor 36A, and the transistor 34B and the transistor 36B respectively form a differential switch circuit. The transistor 34A has a constant current source 50A and a transistor 52A, and the transistor 34B has a constant current source 50B and a transistor 52B and a transistor 36A. Is provided with a constant current source 54A and a transistor 56A, and the transistor 36B is provided with a constant current source 54B and a transistor 56B on the base input side.

In addition, the center tap of each coil 2A and 2B and the power supply terminal
A drive voltage V _CC is applied to 58 from the power supply.

Then, a side selection signal ▲ ▼ is added to the side selection input terminals 60 of the coils 2A and 2B, and this side selection signal ▲
▼ is a resistor 62B, 6 on the base of the transistor 30B, 32B.
Transistors 30A, 32A as well as being added via 4B
After being inverted by the inverter 66 to the base of the resistor 62A, 64A
Added via. Therefore, the side selection signal ▲
When ▼ is at L level, the transistors 30B and 32B are turned off by the input, but the transistors 30A and 32A are cut off.
Since the inverted H (high) level input is applied to the base of the transistors, the transistors 30A and 32A are turned on. In this case, each terminal of the coil 2A is grounded through the damping resistors 4A and 6A and the capacitors 22A and 24A. Further, when the side selection signal ▲ ▼ is at the H level, the transistors 30A and 32A are cut off and the transistors 30B and 32B are turned on. In this case, the terminals of the coil 2B are connected to the damping resistors 4B and 6B and the capacitor 22B. Grounded through 24B.

The input terminal 68 has a write data signal WD and the input terminal 70
A write enable signal WG is added to. The flip-flop circuit 72 receives the write data signal WD at the T input,
This input generates a non-inverted output Q and an inverted output, and the write enable signal WG is sent through the inverter 73.
It is reset by the inversion signal of.

The non-inverted output Q of the flip-flop circuit 72 is the AND circuit 74A,
74B and its inverted output are added to AND circuits 76A and 76B, respectively. In the AND circuits 74A and 76A, the non-inverted output Q and inverted output of the flip-flop circuit 72 and the write enable signal WG applied through the NOR circuit 78 are provided. The logical product of the inverted signal and the inverted logical sum of the side selection signal ▲ ▼ is taken,
Further, in the AND circuits 74B and 76B, the flip-flop circuit 72
AND of the non-inverted output Q and the inverted output of the write enable signal WG applied through the NOR circuit 80 and the inverted signal of the inverted signal of the side selection signal ▲ ▼.

Therefore, when the side selection signal ▲ ▼ is at L level, the transistors 30A and 32A become conductive and NOR
The generation condition of the H output of the circuit 78 is satisfied, and the operation on the coil 2A side is selected. At this time, the AND condition is alternately established in the AND circuits 74A and 76A by the write data signal WD and the write enable signal WG, and the H output is obtained alternately. As a result, the transistors 52A and 56A are alternately turned on, which causes the transistors 36A and 34A to be turned on, so that the constant current source 40 passes through the transistor 34A or the transistor 36A from the coil 2A.
A write current I _WR, which is a magnetizing current, flows through the magnetic recording medium, and necessary recording data is magnetically written on the magnetic recording medium from the magnetic head on the coil 2A side.

When the side selection signal ▲ ▼ is at H level, the transistors 30B and 32B are turned on, and the H output generation condition of the NOR circuit 80 is satisfied, so that the operation on the coil 2B side is selected. At this time, the AND condition is alternately established in the AND circuits 74B and 76B by the write data signal WD and the write enable signal WG, and the H output is obtained alternately. As a result, the transistors 52B and 56B are alternately turned on, and the transistors 36B and 34B are turned on, so that the write current I _WR, which is a magnetizing current, flows from the constant current source 40 to the coil 2B through the transistor 34B or the transistor 36B. Necessary recording data is magnetically written on the magnetic recording medium from the magnetic head on the coil 2B side.

Then, the transistors 30A and 32A are conducted and the coil 2A is selected, and the transistors 30B and 32B are conducted and the coil 2A is selected.
If 2B is selected, damping resistors 4A, 6A, 4B,
Capacitors 22A, 24A, 22B, and 24B are connected in series to 6B, respectively, so that the capacitors 22A, 24A, 22B, and 24B block the direct current, and the power consumption due to the direct current is suppressed.

Further, the damping effect from the driving side is allocated on the coil 2A side by the impedance circuit composed of the damping resistors 4A and 6A and the capacitors 22A and 24A.
Damping resistors 4B, 6B and capacitors 22B, 24B on the side
Since it is allocated by the impedance circuit according to the above, there is no inconvenience due to the addition of the capacitors 22A, 24A, 22B and 24B.

[Effect of device]

According to this invention, it is possible to magnetically record the recording data on the magnetic recording medium by generating the magnetization reversal according to the required recording data, and reduce the power consumption due to the direct current during driving by adding the capacitor. can do.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the magnetic recording circuit of the present invention, and FIG. 2 is a circuit diagram showing the configuration of a general magnetic recording circuit. 2A, 2B ... Coil 4A, 6A, 4B, 6B ... Damping resistance 22A, 24A, 22B, 24B ... Capacitor 30A, 32A, 30B, 32B ... Transistor (first switching element) 34A, 36A, 34B, 36B ... Transistor (second switching element)

Claims (1)

[Scope of utility model registration request] 1. A first magnetic head which is closed at both ends of a coil of a magnetic head via a damping resistor and a capacitor during operation.
The magnetic recording circuit in which the switching element is installed and a current source for supplying a magnetizing current to the coil is installed through the second switching element.