摘要:
An apparatus and method for determining the output current in a bridge-connected switched transistor output circuit including high-side and low-side transistor switches, typically MOSFETS. The voltage at a common node between the high and low side switches is sensed, and offset in a first circuit by a fixed amount so that the voltage is positive for all positive or negative output currents of interest. The output current is actually determined in a second circuit which receives the offset voltage signal only predetermined times in relation to the on-time of the low side switch. The first circuit includes a current reference source/level shifter and a current mirror circuit formed of a plurality of transistors in a particular circuit configuration. The second circuit is coupled to an output of the first circuit by a gated NMOS transistor at the desired times to provide the current measurement signal. The second circuit includes a second current reference source having substantially the same electrical characteristics as the first current reference source, and a second plurality of transistors respectively matched to the input side circuit transistors, and connected in the same circuit configuration. In the second circuit, the offset signal is compared with high and low reference signals to provide an indication if the output current exceeds an overcurrent limit, either positively or negatively. The sensing circuit is advantageously integrated with the output circuit gate driver in a single IC.
摘要:
A circuit for providing over-current protection, the circuit including a gate driver circuit for controlling a bridge circuit including a half bridge stage having high and low switches. The circuit includes a feedback loop circuit for counting over-current indicators sensed during one or more consecutive PWM cycles; wherein when an over-current indicator is sensed, the low switch is turned OFF for duration of a first time period after which the low switch is turned back ON, to enable determination of an over-current condition where false noise signals are rejected thereby preventing circuit shutdowns due to false over-current condition.
摘要:
A dead-time generator for incorporation in an integrated circuit wherein the integrated circuit includes a high side and low side gate driver and wherein the high side and low side gate driver drive output switches such that a dead-time is provided between on times of the output switches, the dead-time generator comprising a circuit internal to the integrated circuit having an external terminal at which a dead-time setting component is connected, and wherein the dead-time generator comprises a circuit for providing a discrete dead-time for a range of dead-time setting values at the dead-time setting terminal and wherein, for a plurality of ranges of dead-time setting values at the dead-time setting terminal, the dead-time generator generates an associated plurality of discrete dead-times.
摘要:
A circuit for minimizing voltage inrush upon startup in a switching power converter having a switching stage including high and low switches connected at a common node, a feedback loop for maintaining a target output voltage, an output capacitor connected between an output node and the ground, an inductor connected between the common node and the output node, and a control circuit having a first error amplifier for providing a first signal based on a comparison of a reference voltage and voltage provided by the feedback loop, the control circuit including a level switch connected between the ground and the common node, the level switch being controlled in accordance with the first signal, wherein a large inrush current flowing into the output capacitor when the circuit is starting up is minimized.
摘要:
A circuit for minimizing voltage inrush upon startup in a switching power converter having a switching stage including high and low switches connected at a common node, a feedback loop for maintaining a target output voltage, an output capacitor connected between an output node and the ground, an inductor connected between the common node and the output node, and a control circuit having a first error amplifier for providing a first signal based on a comparison of a reference voltage and voltage provided by the feedback loop, the control circuit including a level switch connected between the ground and the common node, the level switch being controlled in accordance with the first signal, wherein a large inrush current flowing into the output capacitor when the circuit is starting up is minimized.
摘要:
A control terminal driver IC for a switching circuit having series connected high and low side output transistors, an associated split power supply and a floating input, the gate drive IC, an exemplary, but non-limiting, example of which is a Class D audio amplifier. The IC includes an input circuit, a voltage to current converter connected to the input circuit, a level shifter formed in a mid well of the IC, which is operative to transfer the input signal to the low side without the need for a power supply input to the mid well, a current to voltage converter on the low side coupled to the level shifter; and an output circuit which is operative to generate control terminal drive signals for the high and low side transistors.
摘要:
A dead-time generator for incorporation in an integrated circuit wherein the integrated circuit includes a high side and low side gate driver and wherein the high side and low side gate driver drive output switches such that a dead-time is provided between on times of the output switches, the dead-time generator comprising a circuit internal to the integrated circuit having an external terminal at which a dead-time setting component is connected, and wherein the dead-time generator comprises a circuit for providing a discrete dead-time for a range of dead-time setting values at the dead-time setting terminal and wherein, for a plurality of ranges of dead-time setting values at the dead-time setting terminal, the dead-time generator generates an associated plurality of discrete dead-times.
摘要:
An integrated noise isolation circuit on a single silicon substrate die having a structural arrangement that minimizes noise. The integrated circuit including a noise sensitive circuit including an input stage; a noise generating circuit including an output stage; at least one high voltage level shift circuit coupling the noise generating and noise sensitive circuits for transferring a signal from the input to the output stage; and at least one floating structure for isolating influence of the noise.
摘要:
A control terminal driver IC for a switching circuit having series connected high and low side output transistors, an associated split power supply and a floating input, the gate drive IC, an exemplary, but non-limiting, example of which is a Class D audio amplifier. The IC includes an input circuit, a voltage to current converter connected to the input circuit, a level shifter formed in a mid well of the IC, which is operative to transfer the input signal to the low side without the need for a power supply input to the mid well, a current to voltage converter on the low side coupled to the level shifter; and an output circuit which is operative to generate control terminal drive signals for the high and low side transistors.
摘要:
An apparatus and method for determining the output current in a bridge-connected switched transistor output circuit including high-side and low-side transistor switches, typically MOSFETS. The voltage at a common node between the high and low side switches is sensed, and offset in a first circuit by a fixed amount so that the voltage is positive for all positive or negative output currents of interest. The output current is actually determined in a second circuit which receives the offset voltage signal only predetermined times in relation to the on-time of the low side switch. The first circuit includes a current reference source/level shifter and a current mirror circuit formed of a plurality of transistors in a particular circuit configuration. The second circuit is coupled to an output of the first circuit by a gated NMOS transistor at the desired times to provide the current measurement signal. The second circuit includes a second current reference source having substantially the same electrical characteristics as the first current reference source, and a second plurality of transistors respectively matched to the input side circuit transistors, and connected in the same circuit configuration. In the second circuit, the offset signal is compared with high and low reference signals to provide an indication if the output current exceeds an overcurrent limit, either positively or negatively. The sensing circuit is advantageously integrated with the output circuit gate driver in a single IC.