Reconfigurable analog baseband for a single-chip dual-mode transceiver

• US 7,283,840 B2
• Filed: 02/06/2004
• Issued: 10/16/2007
• Est. Priority Date: 02/07/2003
• Status: Active Grant

• Current Assignee: Chrontel, Inc.
• Original Assignee: Chrontel, Inc.
• Inventors: Cho, Thomas
• Primary Examiner(s): Anderson; Matthew D.
• Assistant Examiner(s): TRAN, TUAN A
• Application Number:
  US10/773,609
• Publication Number:
  US 20040162023A1
• Time in Patent Office: 1,348 Days
• Field of Search: 455/550.1, 455/552.1, 455/553.1, 455 411- 412, 455 78- 88, 4551271-1275, 455/232.1, 455/233.1, 455/234.2, 4552451-2452, 455339-340, 330 98-100
• US Class Current: 455/552.1
• CPC Class Codes: H04B 1/406 with more than one transmission mode, e.g. analog and digital modes
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

A dual-mode analog baseband circuit is implementable on a single IC with reduced chip area. The baseband portion of the IC includes a single dual-mode complex filter that is reconfigurable to be a filter for Bluetooth signals or for wireless local area network (wireless LAN) format signals, such as 802.11b, and includes a single dual-mode amplifier that is reconfigurable to amplify Bluetooth signals or wireless LAN format signals.

Claims

1. A transceiver operable to process Bluetooth compatible signals and wireless local area network compatible (WLAN-compatible) signals, the transceiver comprising:

a radio-frequency unit;

a digital baseband unit configured to generate a mode control signal indicative of a Bluetooth-compatible mode or a WLAN-compatible mode;

a dual-mode filter and amplifier unit having a first Bluetooth-compatible mode and in said second mode, the dual-mode filter and amplifier unit coupled to the radio frequency unit and digital baseband unit and configured to select an operating mode from the first Bluetooth-compatible mode and second WLAN-compatible mode responsive to said mode control signal;

the dual-mode filter and amplifier unit comprising a dual-mode amplifier further comprising;

at least a first stage having an operational amplifier that is in use during both the first Bluetooth-compatible mode and the second WLAN-compatible mode;

at least a first feedback component including at least one resistor;

at least a first switch coupled to said feedback component and said operational amplifier having a first mode and a second mode, such that in said first mode the dual-mode filter and amplifier is operable in said first Bluetooth-compatible mode and the feedback component is disconnected from said operational amplifier and in said second WLAN-compatible mode the dual-mode filter and amplifier is operable in said second WLAN-compatible mode and the feedback component is coupled between an input and an output port of said operational amplifier;

said first feedback component including a resistor and a capacitor coupled to said first feedback component and said first switch; and

the dual-mode filter and amplifier being responsive to the mode control signal through a plurality of switches to change the operation between the Bluetooth-compatible mode configuration and the second WLAN-compatible mode configuration so that;

(i) during operation in the first Bluetooth-compatible mode the dual-mode filter and amplifier is configured as four-stage limiters with AC coupling, a first resistor and a bias current for the operational amplifier setting the amplitude of the limiters output, and a first capacitance C1 and a second resistance R2 setting the AC coupling high-pass corner frequency; and

(ii) during the second WLAN-compatible mode the dual-mode filter and amplifier is configured as a four-stage voltage gain amplifier and the total gain range is set by the resistance ratio (R4/R3) of a fourth resistance R4 to a third resistance R3, and the four voltage gain amplifier stages are DC coupled.

2. A transceiver according to claim 1, wherein the dual-mode filter and amplifier unit comprises a dual-mode filter having at least one component in use during both the first Bluetooth-compatible mode and the second WLAN-compatible mode.

3. A transceiver according to claim 2, wherein said at least one component includes a transistor.

4. A dual-mode amplifier unit having a first Bluetooth-compatible mode, and having a second WLAN-compatible mode, the amplifier comprising:

at least a first stage having an operational amplifier that is in use during both the Bluetooth-compatible mode and the second WLAN-compatible mode;

at least a first feedback component including at least one resistor; and

at least a first switch coupled to said feedback component and said operational amplifier having a first mode and a second mode, such that in said first mode the dual-mode amplifier unit is operable in said first Bluetooth-compatible mode and the feedback component is disconnected from said operational amplifier and in said second mode the dual-mode amplifier unit is operable in said second WLAN-compatible mode and the feedback component is coupled between an input and an output port of said operational amplifier;

said first feedback component includes a resistor and a capacitor coupled to said first feedback component and said first switch;

the dual-mode amplifier unit being responsive to a mode select control signal through a plurality of switches to change the operation between the first Bluetooth-compatible mode and the second WLAN-compatible mode so that;

(i) during operation in the first Bluetooth-compatible mode the dual-mode amplifier unit is configured as four-stage limiters with AC coupling, a first resistor and a bias current for the operational amplifier setting the amplitude of the limiters output, and a first capacitance C1 and a second resistance R2 setting the AC coupling high-pass corner frequency; and

(ii) during the second WLAN-compatible mode the dual-mode amplifier units configured as a four-stage voltage gain amplifier and the total gain range is set by the resistance ratio (R4/R3) of a fourth resistance R4 to a third resistance R3, and the four voltage gain amplifier stages are DC coupled.

5. a dual-mode amplifier unit according to claim 4, wherein said first feedback component includes a resistor.

6. A dual-mode amplifier unit according to claim 4, further comprising a capacitor coupled to said first feedback component and said first switch.

7. A dual-mode amplifier unit according to claim 4, wherein during operation in said first Bluetooth-compatible mode, said first stage operates as a limiter.

8. A dual-mode amplifier unit according to claim 4, wherein during operation in said second WLAN-compatible mode, said first stage operates as a voltage gain amplifier.

9. A transceiver including a dual-mode analog baseband having reduced IC chip area, the transceiver including a dual-mode amplifier unit according to claim 4, coupled to a dual-mode complex filter having a first Bluetooth-compatible mode and a second WLAN-compatible mode and comprising at least one adjustable component operable to select said first Bluetooth-compatible mode or said second WLAN-compatible mode.

10. A transceiver according to claim 9 wherein said filter and said amplifier are formed on a single semiconductor substrate.

11. a dual-mode amplifier unit having a first Bluetooth-compatible mode, and having a second WLAN-compatible mode, the amplifier comprising:

at least a first stage having an operational amplifier;

at least a first feedback component;

at least a first switch coupled to said feedback component and said operational amplifier having a first mode and a second mode, such that in said first mode the dual-mode amplifier unit is operable in said first Bluetooth-compatible mode and the feedback component is disconnected from said operational amplifier and in said second mode the dual-mode amplifier unit is operational in said second WLAN-compatible mode and the feedback component is coupled between an input and an output port of said operational amplifier; and

a capacitor coupled to an output of said operational amplifier and at least a second switch coupled to said capacitor, such that during operation in said first Bluetooth compatible mode, said capacitor at least in part determines an AC coupling corner frequency of said first stage.

12. A method to implement a dual-mode amplifier unit having a first Bluetooth-compatible mode, and having a second WLAN-compatible mode, the method comprising:

providing at least a first stage having an operational amplifier;

providing at least a first feedback component;

coupling at least a first switch having a first mode and a second mode to said feedback component and said operational amplifier, such that in said first mode the dual-mode amplifier unit is operable in said first Bluetooth-compatible mode and the feedback component is disconnected from said operational amplifier and in said second mode the dual-mode amplifier unit is operable in said second WLAN-compatible mode and the feedback component is coupled between an input and an output port of said operational amplifier; and

the dual-mode amplifier unit being responsive to a mode control signal to change the operation between the Bluetooth-compatible mode and the second WLAN-compatible mode so that;

(i) during operation in the first Blue-tooth compatible mode the dual-mode amplifier unit is configured as four-stage limiters with AC coupling, a first resistor and a bias current for the operational amplifier setting the amplitude of the limiters output, and a first capacitance Cl and a second resistance R2 setting the AC coupling high-pass corner frequency; and

(ii) during the second WLAN-compatible mode the dual-mode amplifier units configured as a four-stage voltage gain amplifier and the total gain range is set by the resistance ratio (R4/R3) of a fourth resistance R4 to a third resistance R3, and the four voltage gain amplifier stages are DC coupled.

13. A dual-mode amplifier unit according to claim 12, further comprising a capacitor coupled to said first feedback component and said first switch.

14. A method to provide an IC with reduced chip area, the IC including a dual-mode analog baseband, comprising implementing a filter, implementing an amplifier according to the method of claim 12, and coupling said filter and amplifier.