Circuit for controlling slew rate of a high-side switching element
AssigneeRenesas Electronics Europe GmbH
InventorHans-Juergen Braun
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Abstract
A circuit (11) for controlling slew rate of a high-side switching element (6) in a load switch (5) is described. The circuit includes a variable current source (20) for setting a slew rate. The circuit also includes an amplifier (15) comprising a first input coupled to a fixed voltage source (19), a second input coupled to the variable current source and an output (18) for a drive signal. A feedback path (26) from an input terminal (13), connected or connectable to an output (14) of the switching element, to the second input of the amplifier, includes a series voltage-differentiating element, such as a capacitor (27).
Claims20
A integrated circuit comprising:
- at least one slew-rate controlling circuit, each slew-rate controlling circuit comprising:
- a variable current source for providing a control current for setting a slew rate of a high-side switching element in a load switch, the variable current sourse comprising first and second current sources;
- a differential amplifier comprising:
- a first input coupled to a reference voltage source;
- a second input coupled to the variable current source;
- and
- a differential output for a signal for driving the switching element;
- and
- a feedback path from a circuit input, connected or connectable to an output of the switching element, to the second input of the amplifier, the feedback path including a series voltage-differentiating element,
- wherein the first and second current sources are viable current sources and the variable current source is a programmable current source controllable by control logic to allow the slew rate of the high-side switching element to be varied according to application and adjusted according to load conditions;
- and
- the control logic configured to set the control current for the variable current source.
A circuit for controlling slew rate of a high-side switching element in a load switch, the circuit comprising:
- a variable current source for setting a slew rate;
- a differential amplifier comprising;
- a first input coupled to a deference voltage source;
- a second input coupled to a reference voltage source;
- and
- an output for a signal for driving the switching element, and
- a feedback path from a circuit input, connected or connectable to an output of the switching element, to the second input of the amplifier, the feedback path including a series voltage-differentiating element, and
- a circuit for selectively locking the driving signal in a given state, the circuit comprising differential amplifiers for determining the state of the signal and gates and switches for setting a signal level at the second input to ensure that the state is locked in the given state.
Dependencies are inferred from the claim text.