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US 2004/0201429 A1Published application
Power supply ripple rejection in tuner oscillator stage
AssigneeKoninklijke Philips Electronics N.V.
InventorsYeow Teng Toh, Hendricus Martinus Van Der Wijst, Kam Choon Kwong
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Abstract
A bipolar transistor (Tr) in an oscillator stage of a tuner is provided with a diode (D10) in series with a resistor (R11) coupled between the base of the transistor (Tr) and the reference voltage to which the emitter of the transistor (Tr) is coupled. The diode (D10) allows a decreased resistor (R11) value which causes the supply voltage ripple (Vr1) on the collector originating from the base to decrease so as to better compensate the supply ripple (Vr2) on the collector directly originating from the supply voltage (Vs).
Claims5
A tuner oscillator stage comprising:
- a transistor (Tr) having a control electrode, and two electrodes of a main current path,
- a first impedance (R10) being coupled between the control electrode and a first terminal (Vbs),
- a second impedance (R11) being coupled between the control electrode and a second terminal (G),
- a third impedance (R12) being coupled between one of the two electrodes of the main current path and the second terminal (G), and
- an element (D10) being arranged in series with the second impedance (R11), the element (D10) having a low impedance for AC current and a well-defined voltage drop for DC current, the first and the second terminal being arranged to receive a power supply voltage (Vbs).
2 more elements
Dependencies are inferred from the claim text.