Controller and self-oscillation DC-DC converter including the controller
A controller includes: first to third input terminals; connection terminals; an output terminal; a first rectifying element, connected between the first input terminal and the second input terminal with a direction from the second input terminal to the first input terminal as a forward direction; a second rectifying element, connected between a connection point between the first input terminal and the first rectifying element and the output terminal with a direction from the connection point to the output terminal as a forward direction; an FET circuit, including a first depletion type FET and at least one other FET; a resistor, connected to the second input terminal and the third input terminal; and a clamp circuit, clamping a voltage of the third input terminal to a predetermined voltage.
1 . A controller, comprising:
a first input terminal;
a second input terminal;
a third input terminal;
an output terminal;
a switching element circuit, including a first depletion type field effect transistor and at least one field effect transistor containing a gate connected to a gate of the first depletion type field effect transistor, a source connected to a source of the first depletion type field effect transistor, and a drain, the at least one field effect transistor including a plurality of enhancement type field effect transistors;
a first connector, including a terminal connected to a drain of the first depletion type field effect transistor included in the switching element circuit;
a second connector, including each terminal respectively connected to a drain of the plurality of the enhancement type field effect transistors included in the switching element circuit;
a first rectifying element, connected between the first input terminal and the second input terminal with a direction from the second input terminal to the first input terminal as a forward direction;
a second rectifying element, connected between a connection point between the first input terminal and the first rectifying element and the output terminal with a direction from the connection point to the output terminal as a forward direction;
a resistor, having a first end connected to a gate of the first depletion type field effect transistor and the third input terminal and a second end connected to the second input terminal; and
a clamp circuit, clamping a voltage of the third input terminal to a predetermined voltage.
2 . The controller according to claim 1 , further comprising: a second field effect transistor connected in parallel with the resistor.
3 . The controller according to claim 2 , further comprising: a control circuit, generating a control signal for any one of a first signal level and a second signal level based on whether a voltage difference between a voltage of the second input terminal and a voltage of the output terminal is larger than a reference voltage and supplying the control signal to a gate of the second field effect transistor.
4 . The controller according to claim 2 , further comprising a control circuit,
wherein the control circuit comprises:
a resistor divider circuit coupled between the output terminal and the second input terminal; and
a comparator comparing a divided voltage from a node of the resistor divider circuit with a reference voltage, the comparator comprising an output terminal of the comparator coupled to the gate of the second field effect transistor.
5 . The controller according to claim 1 , wherein in response to a ratio Wd 1 /Ld 1 of a gate width Wd 1 to a gate length Ld 1 of the first depletion type field effect transistor being set as a reference,
the first depletion type field effect transistor of the switching element circuit is configured such that a ratio of a gate width to a gate length is a power of 2 relative to the ratio Wd 1 /Ld 1 .
6 . The controller according to claim 1 , wherein in response to the switching element circuit comprising at least one enhancement type field effect transistor including a first enhancement type field effect transistor and a ratio We 1 /Le 1 of a gate width We 1 to a gate length Le 1 of the first enhancement type field effect transistor being set as a reference,
the first enhancement type field effect transistor of the switching element circuit is configured such that a ratio of a gate width to a gate length is a power of 2 relative to the ratio We 1 /Le 1 .
7 . The controller according to claim 1 , wherein the first rectifying element, the second rectifying element, the field effect transistor of the switching element circuit, and the clamp circuit are integrated as an integrated circuit.
8 . A self-oscillation DC-DC converter, comprising:
the controller according to claim 1 ; and
a transformer, including:
a primary side first terminal;
a primary side second terminal, connected to any one of each terminal included in the first connector; a secondary side first terminal, connected to the third input terminal through a first capacitor and to the first input terminal through a second capacitor; and
a secondary side second terminal.
9 . The controller according to claim 1 , wherein the first depletion type field effect transistor comprises a drain coupled to the terminal of the first connector, and the plurality of the enhancement type field effect transistors coupled in parallel with the first depletion type field effect transistor respectively comprises a drain coupled to each terminal of the second connector.
10 . The controller according to claim 1 , wherein the first connector and the second connector are structurally separated from each other to allow selective connection to a primary side of a power supply device based on an internal resistance of the power supply device.
11 . The controller according to claim 1 , wherein the first connector and the second connector are isolated from each other.
12 . A controller, comprising:
a first input terminal;
a second input terminal;
a third input terminal;
an output terminal;
a switching element circuit, including a first depletion type field effect transistor and at least one field effect transistor containing a gate connected to a gate of the first depletion type field effect transistor, a source connected to a source of the first depletion type field effect transistor, and a drain, the at least one field effect transistor including a second depletion type field effect transistor and at least one enhancement type field effect transistor;
a first connector, including each terminal respectively connected to a drain of the first and second depletion type field effect transistors included in the switching element circuit;
a second connector, including each terminal respectively connected to a drain of the at least one enhancement type field effect transistor included in the switching element circuit;
a first rectifying element, connected between the first input terminal and the second input terminal with a direction from the second input terminal to the first input terminal as a forward direction;
a second rectifying element, connected between a connection point between the first input terminal and the first rectifying element and the output terminal with a direction from the connection point to the output terminal as a forward direction;
a resistor, having a first end connected to a gate of the first depletion type field effect transistor and the third input terminal and a second end connected to the second input terminal; and
a clamp circuit, clamping a voltage of the third input terminal to a predetermined voltage.
13 . The controller according to claim 12 , further comprising: a second field effect transistor connected in parallel with the resistor.
14 . The controller according to claim 13 , further comprising: a control circuit, generating a control signal for any one of a first signal level and a second signal level based on whether a voltage difference between a voltage of the second input terminal and a voltage of the output terminal is larger than a reference voltage and supplying the control signal to a gate of the second field effect transistor.
15 . The controller according to claim 12 , wherein in response to a ratio Wd 1 /Ld 1 of a gate width Wd 1 to a gate length Ld 1 of the first depletion type field effect transistor being set as a reference,
the first depletion type field effect transistor of the switching element circuit is configured such that a ratio of a gate width to a gate length is a power of 2 relative to the ratio Wd 1 /Ld 1 .
16 . The controller according to claim 12 , wherein in response to the switching element circuit comprising at least one enhancement type field effect transistor including a first enhancement type field effect transistor and a ratio We 1 /Le 1 of a gate width We 1 to a gate length Le 1 of the first enhancement type field effect transistor being set as a reference,
the first enhancement type field effect transistor of the switching element circuit is configured such that a ratio of a gate width to a gate length is a power of 2 relative to the ratio We 1 /Le 1 .
17 . The controller according to claim 12 , wherein the first rectifying element, the second rectifying element, the field effect transistor of the switching element circuit, and the clamp circuit are integrated circuits.
18 . A self-oscillation DC-DC converter, comprising:
the controller according to claim 12 ; and
a transformer, comprising: a primary side first terminal; a primary side second terminal, connected to any one of each terminal included in the first connector; a secondary side first terminal, connected to the third input terminal through a first capacitor and to the first input terminal through a second capacitor; and a secondary side second terminal.