摘要:
A pulse width modulation system including a pulse width modulation stage for generating a pulse width modulated signal in response to an input signal and an other pulse width modulation stage for generating an other pulse width modulated signal in response to an other input signal. Additional circuitry ensures that transitions of the pulse width modulated signal and the other pulse width modulated signal are spaced in time by a selected amount for small levels of the input signal.
摘要:
A pulse width modulation circuit for driving a full-bridge output load includes a pulse width modulation stage for generating, from an input data stream, a pulse width modulated data stream for driving a terminal of a full-bridge output load and another pulse width modulated data stream for driving another terminal of the full bridge output load. A delay circuit delays the another pulse width modulated data stream relative to the pulse width modulated data stream such that edges of the another pulse width modulated data stream and edges of the pulse width modulated data stream are temporally spaced.
摘要:
A centered-pulse consecutive edge modulation (CEM) method and apparatus provides a pulse output that advantageously exploits the full edge update rate of the CEM while providing substantially centered pulses. The method and apparatus also operate without substantial delay in the input control path. The apparatus includes a delta-sigma noise shaping modulator followed by a CEM that receives an output of the delta-sigma modulator quantizer. A non-linear correction signal is applied with polarity alternating at each edge and is applied to the quantizer input or is designed into the quantizer transfer function. The non-linear correction signal compensates for the noise-shaping modulator output such that the expected rising edge and falling edge widths of the CEM output pulses are substantially equal with respect to a DC input to the delta-sigma modulator.
摘要:
A loop filter device and method for implementing a loop filter for a phase locked loop (“PLL”) circuit, which locks a frequency of a signal to a reference frequency, are disclosed. The loop filter includes a proportional path circuit and an integral path circuit. The proportional path circuit receives a charge pump output and determines and holds a charge to be directed to or taken from a PLL circuit throughout an update period based on a detected phase difference for the update period for locking a frequency of a signal for a PLL circuit to a reference frequency. The integral path circuit is coupled to the proportional path circuit, and the integral path circuit receives another charge pump output and tracks a total charge level for the PLL circuit based on phase differences for present and prior update periods.
摘要:
A loop filter device and method for implementing a loop filter for a phase locked loop (“PLL”) circuit, which locks a frequency of a signal to a reference frequency, are disclosed. The loop filter includes a proportional path circuit and an integral path circuit. The proportional path circuit receives a charge pump output and determines and holds a charge to be directed to or taken from a PLL circuit throughout an update period based on a detected phase difference for the update period for locking a frequency of a signal for a PLL circuit to a reference frequency. The integral path circuit is coupled to the proportional path circuit, and the integral path circuit receives another charge pump output and tracks a total charge level for the PLL circuit based on phase differences for present and prior update periods.
摘要:
A voltage dropping element is connected in series with the conduction paths of first and second IGFETs, of complementary conductivity, between first and second terminals coupled to first (e.g. 5 volts) and second (e.g. 0 volt) voltage levels, respectively. The gates of the IGFETs are connected to an input terminal to which is applied TTL level signals (e.g. 0.4 to 2.4 volts) and their drains are connected to an output node. When the "high" TTL level (e.g. 2.4 volt) is present, the voltage dropping element reduces the effective gate-to-source voltage (V.sub.GS) of the first IGFET, reducing its conductivity, increasing its effective impedance substantially, and enabling the second IGFET to drive the output node to the second voltage level with little power dissipation. When the "low" TTL input (e.g. 0.4 volt) is present, the second IGFET is turned-off while the first IGFET is turned-on, driving the output node to the voltage at the first power terminal less the voltage drop of the voltage dropping element. A regenerative latch circuit connected to the output node senses the turn-on of the first IGFET and couples the output node to the voltage at the first power terminal eliminating the voltage offset at the output node due to the voltage dropping element.