Patent classifications
H03F3/3035
Reference precharge system
A precharge circuit comprises a gain amplifier, a comparator, a reservoir capacitor, a switch, a current source, and a switching network. The gain amplifier has a gain G1 and receives an input voltage Vrefp. The gain amplifier outputs an amplified voltage G1Vrefp to the comparator, which compares G1Vrefp to a voltage across the reservoir capacitor. The comparator outputs a control signal for the switch based on the comparison. The switch couples the current source to the reservoir capacitor. The current from the current source charges the reservoir capacitor. The switching network couples the reservoir capacitor to an output of the precharge circuit during a first operating mode and provides the input voltage Vrefp to the output during a second operating mode.
REFERENCE PRECHARGE SYSTEM
A precharge circuit comprises a gain amplifier, a comparator, a reservoir capacitor, a switch, a current source, and a switching network. The gain amplifier has a gain G1 and receives an input voltage Vrefp. The gain amplifier outputs an amplified voltage G1Vrefp to the comparator, which compares G1Vrefp to a voltage across the reservoir capacitor. The comparator outputs a control signal for the switch based on the comparison. The switch couples the current source to the reservoir capacitor. The current from the current source charges the reservoir capacitor. The switching network couples the reservoir capacitor to an output of the precharge circuit during a first operating mode and provides the input voltage Vrefp to the output during a second operating mode.
Managing a shoot-through condition in a component containing a push-pull output stage
Shoot-through condition in a component containing an amplifier with a push-pull output stage is managed. A first current in a first transistor of the output stage is mirrored to generate a first mirrored current. A second current in a second transistor of the output stage is mirrored to generate a second mirrored current. A sum of the first mirrored current and said second mirrored current is generated. When a magnitude of the sum exceeds a first pre-determined threshold, a respective control voltage of the first transistor and the second transistor is adjusted to reduce the first current and the second current at least until the sum falls below a second pre-determined threshold. In an embodiment, the first pre-determined threshold equals the second pre-determined threshold. In an embodiment, the component is a class-L power amplifier.
Data receiver and controller for DDR memory
A data receiver for a double data rate (DDR) memory includes a first stage circuit and a second stage circuit. The first stage circuit is deployed for receiving a single-ended signal from the DDR memory and converting the single-ended signal into a pair of differential signals. The second stage circuit, coupled to the first stage circuit, is deployed for receiving the differential signals from the first stage circuit and converting the differential signals into an output signal. Both of the first stage circuit and the second stage circuit are implemented in a core voltage domain.
MANAGING A SHOOT-THROUGH CONDITION IN A COMPONENT CONTAINING A PUSH-PULL OUTPUT STAGE
Shoot-through condition in a component containing an amplifier with a push-pull output stage is managed. A first current in a first transistor of the output stage is mirrored to generate a first mirrored current. A second current in a second transistor of the output stage is mirrored to generate a second mirrored current. A sum of the first mirrored current and said second mirrored current is generated. When a magnitude of the sum exceeds a first pre-determined threshold, a respective control voltage of the first transistor and the second transistor is adjusted to reduce the first current and the second current at least until the sum falls below a second pre-determined threshold. In an embodiment, the first pre-determined threshold equals the second pre-determined threshold. In an embodiment, the component is a class-L power amplifier.
Low-noise current-in class D amplifier with slew rate control mechanism
A circuit applied to speaker includes a tri-level current DAC and a class D amplifier. The current DAC is arranged to receive a digital signal to generate a current signal, and the class D amplifier is arranged to directly receive the current from the current DAC and to amplify the current signal to generate an output signal. SNR performance is well improved class D amplifier due to small signal noise reduced by preceding tri-level DAC. In addition, the circuit further includes a driving stage, and a gate-drain voltage of a power transistor within the driving stage can be controlled to set the appropriate slew rate.
Differential amplifier circuit
Provided is a differential amplifier circuit having a low current consumption and a small circuit area. The differential amplifier circuit is formed as a drain grounding circuit (source follower circuit), which includes two stages of output transistors that are connected to two stages of amplifier circuits in series, and is configured to control one of the two output transistors by output from the amplifier circuit in the first stage, and to control another of the two output transistors by output from the amplifier circuit in the second stage.
LOW-NOISE CURRENT-IN CLASS D AMPLIFIER WITH SLEW RATE CONTROL MECHANISM
A circuit applied to speaker includes a tri-level current DAC and a class D amplifier. The current DAC is arranged to receive a digital signal to generate a current signal, and the class D amplifier is arranged to directly receive the current from the current DAC and to amplify the current signal to generate an output signal. SNR performance is well improved class D amplifier due to small signal noise reduced by preceding tri-level DAC. In addition, the circuit further includes a driving stage, and a gate-drain voltage of a power transistor within the driving stage can be controlled to set the appropriate slew rate.
DIFFERENTIAL AMPLIFIER CIRCUIT
Provided is a differential amplifier circuit having a low current consumption and a small circuit area. The differential amplifier circuit is formed as a drain grounding circuit (source follower circuit), which includes two stages of output transistors that are connected to two stages of amplifier circuits in series, and is configured to control one of the two output transistors by output from the amplifier circuit in the first stage, and to control another of the two output transistors by output from the amplifier circuit in the second stage.