Transit mixer with current mode input
US5642071A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 7, 1995 |
| Grant date | Jun 24, 1997 |
| Priority date | — |
| Expiry date | Nov 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03D7/1491
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A differential mixer (DM) used in a telecommunication radio transmitter able to operate with a 3 Volt supply includes a silicon bipolar cross-connected pair of differential amplifiers (A; B) for receiving a first input voltage (LO) at a high frequency, a pair of current sources (I1; I2), and a voltage-to-current MOS converter (VIC) for receiving a second input voltage (VIN) at a lower frequency. The converter is adapted to convert the low frequency voltage to a differential current (INN) and is coupled to the junction points of the amplifiers and the current sources. The converter further includes a regulated differential cascode circuit (P1; P2) to which the low frequency input voltage (VIN) is applied via resistors (RI1; RI2) and which is coupled to the supply terminals (VCC; GND) of the mixer via two pairs of constant current sources (PB1, PB2; NB1, NB2) respectively. Preferably, a constant reference voltage terminal (VCC/2) is applied to the gate electrode of the transistors (P1; P2) of the cascode circuit via an operational amplifier (O1; O2).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.