Drive circuit, tactile sensation generator, and method for controlling drive circuit

1 . A drive circuit comprising:

a first switching element inserted in a current path connecting a load with a resonance frequency to a reference potential point;

a drive element having a first input terminal to which a load signal obtained by converting a current flowing in the current path into a voltage is input, a second input terminal to which a first control signal that serves as a reference for operation of the first switching element is input, and an output terminal connected to a control terminal of the first switching element;

a second switching element inserted in a first connection path connecting the output terminal of the drive element and the first input terminal of the drive element;

a first resistor inserted in a second connection path connecting the output terminal of the drive element and the control terminal of the first switching element; and

a second resistor inserted in a branch path connecting the reference potential point to a branch point that branches off from the second connection path between the first resistor and the control terminal of the first switching element.

2 . The drive circuit according to claim 1 , wherein the load is an inductive load having the resonance frequency, the first and second switching elements are field effect transistors, and the drive element is an operational amplifier.

3 . The drive circuit according to claim 1 , further comprising:

a controller configured to control the drive element and the second switching element, wherein

the controller is further configured to:

output a first control signal that has a cycle corresponding to the resonance frequency of the load and that is turned on and off within each cycle to the drive element, element;

output a second control signal that has the cycle corresponding to the resonance frequency of the load and that is turned on and off within each cycle to the second switching element; and

perform control such that a start of the cycle of the first control signal and a start of the cycle of the second control signal are matched and the first control signal is repeatedly turned on during an off period of the second control signal.

4 . The drive circuit according to claim 3 , wherein the controller is connected to the second input terminal of the drive element and a control terminal of the second switching element, and

the controller is further configured to output the first control signal to the second input terminal and output the second control signal to the control terminal of the second switching element.

5 . The drive circuit according to claim 3 , wherein

the second control signal is turned off in a first half of the cycle of the resonance frequency of the load and turned on in a remaining half of the cycle, and

the first control signal is repeatedly turned on within a first quarter of the cycle of the resonance frequency of the load and is turned off in the remaining three-quarters of the cycle.

6 . The drive circuit according to claim 5 , wherein the first control signal is repeatedly turned on with an increasing duty ratio of a pulse width modulation pulse signal within the first quarter of the cycle.

7 . A tactile sensation generator comprising:

the drive circuit according to claim 1 , and

the load.

8 . A method for controlling a drive circuit, wherein

the drive circuit includes:

a first switching element inserted in a current path connecting a load with a resonance frequency to a reference potential point;

a drive element that performs drive control of the first switching element;

a second switching element inserted in a first connection path connecting an output terminal of the drive element to a first input terminal of the drive element; and

a controller configured to control the drive element and the second switching element, and

the method for controlling the drive circuit by causing the controller to execute a process, the method comprising executing on the controller the steps of:

outputting a first control signal that has a cycle corresponding to the resonance frequency of the load and that is turned on and off within each cycle to the drive element;

outputting a second control signal that has the cycle corresponding to the resonance frequency of the load and that is turned on and off within each cycle to the second switching element; and

performing control such that a start of the cycle of the first control signal and a start of the cycle of the second control signal are matched and the first control signal is repeatedly turned on during an off period of the second control signal.

9 . The method for controlling a drive circuit according to claim 8 , wherein

the second control signal is turned off in a first half of the cycle of the resonance frequency of the load and turned on in a remaining half of the cycle, and

the first control signal is repeatedly turned on within a first quarter of the cycle of the resonance frequency of the load and is turned off in the remaining three-quarters of the cycle.

10 . The method for controlling a drive circuit according to claim 9 , wherein the first control signal is repeatedly turned on with an increasing duty ratio of a pulse width modulation pulse signal within the first quarter of the cycle.

11 . A drive circuit comprising:

a first switching element inserted in a current path connecting a load with a resonance frequency to a reference potential point;

a drive element having a first input terminal to which a load signal obtained by converting a current flowing in the current path into a voltage is input, a second input terminal to which a first control signal that serves as a reference for operation of the first switching element is input, and an output terminal connected to a control terminal of the first switching element;

a second switching element inserted in a first connection path connecting the output terminal of the drive element and the first input terminal of the drive element; and

a controller configured to control the drive element and the second switching element, wherein

the controller is further configured to:

output a first control signal that has a cycle corresponding to the resonance frequency of the load and that is turned on and off within each cycle to the drive element;

output a second control signal that has the cycle corresponding to the resonance frequency of the load and that is turned on and off within each cycle to the second switching element; and

perform control such that a start of the cycle of the first control signal and a start of the cycle of the second control signal are matched and the first control signal is repeatedly turned on during an off period of the second control signal.

12 . The drive circuit according to claim 11 , further comprising:

a first resistor inserted in a second connection path connecting the output terminal of the drive element and the control terminal of the first switching element.

13 . The drive circuit according to claim 12 , further comprising:

a second resistor inserted in a branch path connecting the reference potential point to a branch point that branches off from the second connection path between the first resistor and the control terminal of the first switching element.

14 . The drive circuit according to claim 11 , wherein the load is an inductive load having the resonance frequency, the first and second switching elements are field effect transistors, and the drive element is an operational amplifier.

15 . The drive circuit according to claim 11 , wherein the controller is connected to the second input terminal of the drive element and a control terminal of the second switching element, and

the controller is further configured to output the first control signal to the second input terminal and output the second control signal to the control terminal of the second switching element.

16 . The drive circuit according to claim 11 , wherein

the second control signal is turned off in a first half of the cycle of the resonance frequency of the load and turned on in a remaining half of the cycle, and

the first control signal is repeatedly turned on within a first quarter of the cycle of the resonance frequency of the load and is turned off in the remaining three-quarters of the cycle.

17 . The drive circuit according to claim 16 , wherein the first control signal is repeatedly turned on with an increasing duty ratio of a pulse width modulation pulse signal within the first quarter of the cycle.

18 . A tactile sensation generator comprising:

the drive circuit according to claim 11 , and

the load.