Negative feedback amplifier with electrostatic discharge protection circuit
View Patent ↗A negative feedback amplifier which alleviates reduction in band width and effectively protects an amplifier from electrostatic discharge (ESD). A node is provided at the midpoint of a feedback resistor connected between an output terminal and an input terminal of an amplifier. Each of ESD protective diodes are connected between the node and respective power terminals. ESD threshold voltage and band width vary in accordance with the resistance of a resistor between the input terminal and the node. Setting the resistance of the resistor at 10 to 100Ω makes it possible to secure the necessary ESD threshold voltage while hardly reducing band width.
1. A negative feedback amplifier with a feedback resistor connected between an output terminal and an input terminal of an amplifier, the amplifier being powered from a first power terminal and a second power terminal, the negative feedback amplifier comprising:
a division node between a first resistor on an input terminal side of the amplifier and a second resistor on an output terminal side of the amplifier, the first and second resistors together constitute said feedback resistor;
a first diode having a first electrode connected to said first power terminal, and a second electrode connected to said division node; and
a second diode having a first electrode connected to said second power terminal, and a second electrode connected to said division node.
2. The negative feedback amplifier according to claim 1 , further comprising:
a third diode having a first electrode connected to said division node, and a second electrode connected to said first power terminal; and
a fourth diode having a first electrode connected to said division node, and a second electrode connected to said second power terminal.
3. A negative feedback amplifier with a feedback resistor connected between an output terminal and an input terminal of an amplifier, the amplifier being powered from a first power terminal and a second power terminal, the negative feedback amplifier comprising:
a first division node and a second division node, said first division node provided between a first resistor and a second resistor, and said second division node provided between the second resistor and a third resistor, said first to third resistors being arranged from an input terminal side of the amplifier to an output terminal side of the amplifier in order, and together constituting said feedback resistor;
a first diode having a first electrode connected to said first power terminal, and a second electrode connected to said first division node;
a second diode having a first electrode connected to said second power terminal, and a second electrode connected to said first division node;
a third diode having a first electrode connected to said second division node, and a second electrode connected to said first power terminal; and
a fourth diode having a first electrode connected to said second division node, and a second electrode connected to said second power terminal.
4. The negative feedback amplifier according to claim 1 , wherein said diodes each comprise a plurality of elements connected in series.
5. The negative feedback amplifier according to claim 2 , wherein said diodes each comprise a plurality of elements connected in series.
6. The negative feedback amplifier according to claim 3 , wherein said diodes each comprise a plurality of elements connected in series.
7. A negative feedback amplifier with a feedback resistor connected between an output terminal and an input terminal of an amplifier, the amplifier being powered from a first power terminal and a second power terminal, the negative feedback amplifier comprising:
a division node between a first resistor on an input terminal side of the amplifier and a second resistor on an output terminal side of the amplifier, the first and second resistors together constitute said feedback resistor;
a first diode having a first electrode connected to said first power terminal, and a second electrode connected to a connection node;
a second diode having a first electrode connected to said second power terminal, and a second electrode connected to said connection node; and
a third diode having a first electrode connected to said connection node, and a second electrode connected to said division node.
8. A negative feedback amplifier with a feedback resistor connected between an output terminal and an input terminal of an amplifier, the amplifier being powered from a first power terminal and a second power terminal, the negative feedback amplifier comprising:
a first division node and a second division node, said first division node provided between a first resistor and a second resistor, and said second division node provided between the second resistor and a third resistor, said first to third resistors being arranged in order from an input terminal side of the amplifier to an output terminal side of the amplifier, and together constituting said feedback resistor;
a first diode having a first electrode connected to said first power terminal, and a second electrode connected to a first connection node;
a second diode having a first electrode connected to said second power terminal, and a second electrode connected to said first connection node;
a third diode having a first electrode connected to said first connection node, and a second electrode connected to said first division node;
a fourth diode having a first electrode connected to a second connection node, and a second electrode connected to said first power terminal;
a fifth diode having a first electrode connected to said second connection node, and a second electrode connected to said second power terminal; and
a sixth diode having a first electrode connected to said second division node, and a second electrode connected to said second connection node.
9. The negative feedback amplifier according to claim 7 , wherein said first and second diodes each comprise a plurality of elements connected in series.
10. The negative feedback amplifier according to claim 8 , wherein said first, second, fourth and fifth diodes each comprise a plurality of elements connected in series.
11. The negative feedback amplifier according to claim 1 , wherein said first electrode of each of said diodes is an anode, and said second electrode of each of said diodes is a cathode.
12. The negative feedback amplifier according to claim 3 , wherein said first electrode of each of said diodes is an anode, and said second electrode of each of said diodes is a cathode.
13. The negative feedback amplifier according to claim 7 , wherein said first electrode of each of said diodes is an anode, and said second electrode of each of said diodes is a cathode.
14. The negative feedback amplifier according to claim 8 , wherein said first electrode of each of said diodes is an anode, and said second electrode of each of said diodes is a cathode.
15. The negative feedback amplifier according to claim 1 , wherein the amplifier is composed of a high-electron-mobility transistor, and each of said diodes is composed of a Schottky diode formed in a same process as the amplifier.
16. The negative feedback amplifier according to claim 3 , wherein the amplifier is composed of a high-electron-mobility transistor, and each of said diodes is composed of a Schottky diode formed in a same process as the amplifier.
17. The negative feedback amplifier according to claim 7 , wherein the amplifier is composed of a high-electron-mobility transistor, and each of said diodes is composed of a Schottky diode formed in a same process as the amplifier.
18. The negative feedback amplifier according to claim 8 , wherein the amplifier is composed of a high-electron-mobility transistor, and each of said diodes is composed of a Schottky diode formed in a same process as the amplifier.
19. The negative feedback amplifier according to claim 1 , wherein resistance of said first resistor is 10 to 100Ω.
20. The negative feedback amplifier according to claim 3 , wherein resistance of said first resistor is 10 to 100Ω.
21. The negative feedback amplifier according to claim 7 , wherein resistance of said first resistor is 10 to 100Ω.
22. The negative feedback amplifier according to claim 8 , wherein resistance of said first resistor is 10 to 100Ω.