# US 2014/0197890 A1 · Precise current source circuit for bias supply of rf mmic gain block amplifier application > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0197890 A1 - Document ID: US20140197890A1 - Status: Published application - Kind: A1 - Application number: 13/846,409 - Filed: 2013-03-18 - Published: 2014-07-17 - Earliest claimed: 2013-01-17 - Assignees: Microelectronics Technology Inc. - Applicants: Microelectronics Technology, Inc. - Inventors: Ming Che LIOU - Web page: https://patentgrep.com/patent/US20140197890A1 ## CPC - H03F 1/302: {in bipolar transistor amplifiers (H03F1/303, H03F1/305, H03F1/307 take precedence)} - H03F 3/245: {with semiconductor devices only} - H03F: AMPLIFIERS ## Abstract A current source circuit includes a first transistor Q1, a second transistor Q2, a first resistor R1, and a second resistor R2. The first transistor Q1 has a first terminal (collector) coupled with the supply voltage (VCC), a second terminal (base) coupled with the first resistor R1, and a third terminal (emitter) coupled with the second resistor R2. The second transistor Q2 has a first terminal coupled with the second terminal of the first transistor Q1, a second terminal coupled with the third terminal of the first transistor Q1, and a third terminal coupled with the filtering circuit 39. The first resistor R1 is coupled between the supply voltage and a second terminal of the first transistor Q1. The second resistor R2 is coupled between a third terminal of the first transistor Q1 and the filtering circuit 39. ## Claims ### Claim 1 A current source circuit, comprising: a first transistor having a first terminal coupled with a supply voltage; a first resistor coupled between the supply voltage and a second terminal of the first transistor; a second resistor coupled between a third terminal of the first transistor and an output node; and a second transistor having a first terminal coupled with the second terminal of the first transistor, and a second terminal coupled with the third terminal of the first transistor. ### Claim 2 (depends on 1) The current source circuit of claim 1, wherein the second terminal of the second transistor is coupled with a node between the third terminal of the first transistor and the second resistor. ### Claim 3 (depends on 1) The current source circuit of claim 1, wherein the second transistor has a third terminal coupled with the output node. ### Claim 4 (depends on 1) The current source circuit of claim 1, wherein the second transistor is configured to decrease a voltage of the output node as a first current flowing through the first transistor increases. ### Claim 5 (depends on 1) The current source circuit of claim 1, further comprising: a third resistor coupled between the second resistor and the output node; and a third transistor having a first terminal coupled with a third terminal of the second transistor, and a second terminal coupled with a node between the second resistor and the third resistor. ### Claim 6 (depends on 5) The current source circuit of claim 5, wherein the third transistor has a third terminal coupled with the output node. ### Claim 7 (depends on 5) The current source circuit of claim 5, wherein the third transistor is configured to decrease a voltage of the output node as a first current flowing through the first transistor increases. ### Claim 8 A radio frequency signal amplification system, comprising: an amplifier having an input terminal and an output terminal; a filtering circuit coupled with the output terminal; and a current source circuit configured to supply an operation current to the output terminal of the amplifier through the filtering circuit, comprising: is a first transistor having a first terminal coupled with a supply voltage; a first resistor coupled between the supply voltage and a second terminal of the first transistor; a second resistor coupled between a third terminal of the first transistor and the filtering circuit; and a second transistor having a first terminal coupled with the second terminal of the first transistor, and a second terminal coupled with the third terminal of the first transistor. ### Claim 9 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the second terminal of the second transistor is coupled with a node between the third terminal of the first transistor and the second resistor. ### Claim 10 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the second transistor has a third terminal coupled with the filtering circuit. ### Claim 11 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the second transistor is configured to decrease a voltage of the output terminal as the operation current increases. ### Claim 12 (depends on 8) The radio frequency signal amplification system of claim 8, further comprising: a third resistor coupled between the second resistor and the filtering circuit; and is a third transistor having a first terminal coupled with a third terminal of the second transistor, and a second terminal coupled with a node between the second resistor and the third resistor. ### Claim 13 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the third transistor has a third terminal coupled with the filtering circuit. ### Claim 14 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the third transistor is configured to decrease a voltage of the output node as the operation current increases. ### Claim 15 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the current source circuit is configured to limit an average of the operation current in order to not exceed a setting level of the amplifier, and supply a peak current for radio frequency pulse operations of the amplifier. ### Claim 16 (depends on 8) The radio frequency signal amplification system of claim 8, wherein the current source circuit is configured to clamp an average power of the amplifier in order to not exceed a 1 dB compression point (P1 dB). ### Claim 17 A radio frequency signal amplification system, comprising: an amplifier having an input terminal and an output terminal; a filtering circuit coupled with the output terminal; and a current source circuit coupled between a supply voltage and the filtering circuit and configured to supply an operation current to the is output terminal of the amplifier through the filtering circuit; wherein the current source circuit is configured to limit an average of the operation current in order to not exceed a setting level of the amplifier, and supply a peak current for radio frequency pulse operations of the amplifier. ### Claim 18 (depends on 17) The radio frequency signal amplification system of claim 17, wherein the current source circuit is configured to clamp an average power of the amplifier in order to not exceed a 1 dB compression point (P1 dB). ### Claim 19 (depends on 17) The radio frequency signal amplification system of claim 17, wherein the current source circuit comprises: a first transistor having a first terminal coupled with the supply voltage; a first resistor coupled between the supply voltage and a second terminal of the first transistor; a second resistor coupled between a third terminal of the first transistor and the filtering circuit; and a second transistor having a first terminal coupled with the second terminal of the first transistor, and a second terminal coupled with the third terminal of the first transistor. ### Claim 20 (depends on 19) The radio frequency signal amplification system of claim 19, wherein the second terminal of the second transistor is coupled with a node between the third terminal of the first transistor and the is second resistor. ### Claim 21 (depends on 19) The radio frequency signal amplification system of claim 19, wherein the second transistor has a third terminal coupled with the filtering circuit. ### Claim 22 (depends on 19) The radio frequency signal amplification system of claim 19, wherein the second transistor is configured to decrease a voltage of the output terminal as the operation current increases. ### Claim 23 (depends on 19) The radio frequency signal amplification system of claim 19, further comprising: a third resistor coupled between the second resistor and the filtering circuit; and a third transistor having a first terminal coupled with a third terminal of the second transistor, and a second terminal coupled with a node between the second resistor and the third resistor. ### Claim 24 (depends on 23) The radio frequency signal amplification system of claim 23, wherein the third transistor has a third terminal coupled with the filtering circuit. ### Claim 25 (depends on 23) The radio frequency signal amplification system of claim 23, wherein the third transistor is configured to decrease a voltage of the output terminal as the operation current increases.