Attenuator

• US 10,630,264 B2
• Filed: 05/24/2019
• Issued: 04/21/2020
• Est. Priority Date: 12/03/2014
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Mu, Fenghao, Mattisson, Sven
• Primary Examiner(s): Liao, Hsinchun
• Application Number:
  US16/422,651
• Publication Number:
  US 20190280672A1
• Time in Patent Office: 333 Days
• CPC Class Codes: H03G 1/0088 using discontinuously variable devices, e.g. switch-operated
• CPC Class Codes: H03G 1/0094 using switched capacitors
• CPC Class Codes: H03G 2201/106 being attenuating element
• CPC Class Codes: H03H 11/245 using field-effect transistor
• CPC Class Codes: H03H 7/25 comprising an element controlled by an electric or magnetic variable H03H7/27 takes precedence
• CPC Class Codes: H04B 1/40 Circuits
• CPC Class Codes: H04B 7/0608 Antenna selection according to transmission parameters

Abstract

An attenuator for attenuating a signal is disclosed. The attenuator comprises a differential input port with a positive input node and a negative input node to receive the signal; and a differential output port with a positive output node and a negative output node to output the attenuated signal. The attenuator further comprises a first switched resistor network connected between the positive input node and the positive output node; and a second switched resistor network connected between the negative input node and the negative output node. Further a pair of compensation paths is connected to the first and second switched resistor networks for cancellation their parasitic leakages, where a first compensation path is connected between the positive input node and the negative output node, and a second compensation path is connected between the negative input node and the positive output node. The attenuator further comprises a control circuit to generate control signals for controlling the first and second switched resistor networks.

Claims

1. An attenuator for attenuating a signal comprising:

a differential input port with a positive input node and a negative input node to receive the signal;

a differential output port with a positive output node and a negative output node to output the attenuated signal;

a first switched resistor network connected between the positive input node and the positive output node;

a second switched resistor network connected between the negative input node and the negative output node;

a first path connected between the positive input node and the negative output node, the first path comprising one or more switched capacitor branches;

a second path connected between the negative input node and the positive output node; and

a control circuit to generate control signals for controlling the first and second switched resistor networks.

2. The attenuator according to claim 1, wherein the attenuator further comprises a first pair of inductors connected at the differential input port and a second pair of inductors connected at the differential output port.

3. The attenuator according to claim 2, wherein the first and second pair of inductors are mutually coupled inductors.

4. The attenuator according to claim 1, wherein the control circuit is further configured to generate control signals for controlling the pair of compensation paths.

5. The attenuator according to claim 1, wherein each of the first and second switched resistor networks is a Pi type resistor network comprising two switchably variable parallel resistors and one switchably variable series resistor.

6. The attenuator according to claim 5, wherein the switchably variable series resistor comprises one or more switched resistor branches and a by-pass path.

7. The attenuator according to claim 6, wherein the by-pass path comprises a switch, and wherein a bootstrap path comprising a capacitor in series with a resistor is connected between a gate and a drain or source of the switch.

8. The attenuator according to claim 6, wherein each of the one or more switched resistor branches comprises a resistor in series with a switch, and wherein for one or more switches, a bootstrap path comprising a capacitor in series with a resistor is connected between a gate and a drain or source of the switches depending on size of the one or more switches.

9. The attenuator according to claim 5, wherein the switchably variable parallel resistor comprises one or more switched resistor branches connected in series with a resistor.

10. The attenuator according to claim 1, wherein each of the first and second switched resistor networks is a T type resistor network comprising one switchably variable parallel resistor and two switchably variable series resistors.

11. An electronic device comprising an attenuator according to claim 1.

12. The electronic device according to claim 11, wherein the electronic device is a transceiver.

13. The electronic device according to claim 11, wherein the electronic device is a radio base station.

14. The attenuator according to claim 1, wherein one or more of the switched capacitor branches of the first path comprises a capacitor connected in series with a resistor.

15. The attenuator according to claim 14, wherein one or more of the switched capacitor branches of the first path further comprises a switch connected in series with the capacitor and the resistor.

16. The attenuator according to claim 1, wherein the second path comprises one or more switched capacitor branches.

17. The attenuator according to claim 16, wherein one or more of the switched capacitor branches of the second path comprises a capacitor connected in series with a resistor.

18. The attenuator according to claim 17, wherein one or more of the switched capacitor branches of the second path further comprises a switch connected in series with the capacitor and the resistor.