摘要:
A method and circuit for providing a switched current source output has a precharge mode, in which a charge storage device is charged to a reference voltage, and the gate of an output transistor is discharged. In a discharge mode, the charge storage device is discharged to the gate of the output transistor to raise the gate voltage by an amount depending on the charge flow.
摘要:
Disclosed is a class D amplifier comprising a modulation stage having a first input for receiving an input signal and an output for producing a modulated version of the input signal; a plurality of power stages, each power stage being responsive to said modulation stage and comprising a first switch and a second switch coupled in series between a first voltage source and a second voltage source, each power stage comprising an output node between the first switch and the second switch; and a power stage control circuit for measuring the input signal level and enabling a selected number of the power stages as a function of the measured input signal level. A method for controlling such a class D amplifier is also disclosed.
摘要:
The invention concerns a method and signal conversion device for avoiding undesirable noise in the start up of an amplifying device, as well as to an amplifying device including such a signal conversion device. The signal conversion device (12) comprises a variable gain providing unit (Q3, Q4, Q5, Q6), a voltage to current converter (Q1, Q2, R1, R2), a variable gain control unit (22) controlling the variable gain of the variable gain providing unit, and a bias current control unit (20) for controlling a first biasing current (IB1) of the voltage to current converter, for avoiding DC offset originating noise as well as noise originating from components of the signal conversion device.
摘要:
A pulse width modulation (PWM) circuit comprises a first integrator (g m1) with a first feedback capacitor (C1), a second integrator (gm1) with a second feedback capacitor (C2) and a comparator (A0) having a first input (V1) connected to the output of the first integrator (gm1) and a second input (V2) connected to the output of the second integrator (gm2). A connection path comprising a resistor (R2) is established from the output of the first integrator (gm1) to an input of the second integrator (gm2). The first and second feedback capacitors (C1, C2) have capacities with a non-linear factor X(V) and a circuit with an inversely non-linear factor X−1(V) is arranged in the connection path between the output of the first integrator (gm1) and said input of the second integrator (gm2). The PWM circuit may form path of a Class-D amplifier.
摘要:
The invention refers to a power amplifier comprising a first transistor (MH) having a first main channel coupled between a positive power supply terminal (Vdd) and an output terminal (Vout), said first transistor having a control terminal driven by a first gate signal (Vgatehigh) provided by a high driver circuit, which is biased from a first voltage terminal (Vboot). The power amplifier further comprises a second transistor (ML) having a second main channel coupled between the output terminal and a negative power supply terminal (Vss), said second transistor having a second control terminal driven by a second gate signal (Vgatelow) provided by a low driver circuit, which is biased from a second voltage terminal (Vreg), and a switch circuit (10) coupled between the first voltage terminal (Vboot) and the second voltage terminal (Vreg), said switch circuit being controlled by the second gate Signal (Vgatelow).
摘要:
A driver (Highside Driver, Lowside Driver) adapted to drive each of final transistors (MH, ML, Mpower) included in a power amplifier, the driver including: a first plurality of switches (Mpsiow, Mpmoderate, Mpfast) having their respective main current channels coupled between a bias voltage terminal (Vddx) and a control electrode of the respective final transistors (MH, ML, Mpower), said first plurality of switches (Mpsiow, Mpmoderate, Mpfast) being selectively turned ON for enabling a progressive charging of the respective control electrode of the final transistors (MH, ML, MPower), a second plurality of switches (Mnsiow, Mnfast) having their respective main current channels coupled between another bias voltage terminal (Vsource) and the control electrode of the respective final transistors (MH, ML, Mpower), said second plurality of switches (Mnsiow, Mnfast) being selectively switched ON until a current through the respective final transistors (MH, ML, Mpower) changes its polarity.
摘要:
A device (100) for processing data, the device (100) comprising an integrator unit (103, 104) adapted for integrating an input signal (V1) and a correction unit (101, 102) adapted for correcting a clipping integrator unit (103, 104) by forcing a zero-crossing of an output signal (V1, V2) of the integrator unit (103, 104).
摘要:
A class D amplifier (1) comprises an input unit (11) for receiving a digital input signal (Vin), a pulse shaping unit (12) for producing pulse shaped signals in dependence of the input signal (Vin), a comparator unit (13) for comparing the pulse shaped signals and producing a comparator signal, a driver unit (14) for producing driver signals in dependence of the comparator signal, a switching output unit (15) for producing a pulse width modulated output signal (Vout) in dependence of the driver signals, and a feedback unit (16) for feeding the output signal (Vout) back to the pulse shaping unit (12). The input unit (11) comprises a clipping control unit (10) for controlling the duty cycle of the pulse width modulated output signal (Vout).
摘要:
A push-pull amplifier comprises a pulse width modulator with a limiter for limiting the modulation depth, whereby the problem that the output is switched to either highside or lowside is prevented, and thus the carrier frequency is always present in the output spectrum and the bootstrap capacitor is recharged each clock-cycle.