Semiconductor integrated circuit
AssigneeRohm Co., Ltd.
InventorTakenori Kato
Life of this patent
Estimating the term…
Abstract
A pulse modulator receives an analog voltage VIN, and generates a pulse signal that is modulated according to the analog voltage VIN. An output stage generates a switching signal at an output terminal according to the pulse signal. A semiconductor integrated circuit is switchable between (i) a normal mode in which a main signal VMAIN to be used in a normal operating mode is input as the analog voltage VIN to the pulse modulator, and (ii) a test mode in which at least one internal analog signal VAUX generated in the semiconductor integrated circuit is input as the analog voltage VIN to the pulse modulator.
Claims13
A semiconductor integrated circuit comprising:
- an output terminal;
- a pulse modulator that receives an analog voltage, and that generates a pulse signal modulated according to the analog voltage;
- and
- an output stage that generates a switching signal at the output terminal according to the pulse signal,
- wherein the semiconductor integrated circuit is switchable between (i) a normal mode in which a main signal to be used in a normal operating mode is input as the analog voltage to the pulse modulator, and (ii) a test mode in which at least one internal analog signal generated in the semiconductor integrated circuit is input as the analog voltage to the pulse modulator, and
- wherein the pulse modulator comprises:
- an error amplifier that receives, via an inverting input terminal thereof, the analog voltage and a voltage fed back from the output terminal, and that receives a reference voltage via a non-inverting input terminal thereof;
- and
- a comparator that compares an output voltage of the error amplifier with a cyclic voltage, and that outputs a pulse signal that indicates a comparison result.
A semiconductor integrated circuit comprising:
- an output terminal;
- a pulse modulator that receives an analog voltage, and that generates a pulse signal modulated according to the analog voltage;
- and
- an output stage that generates a switching signal at the output terminal according to the pulse signal,
- wherein the semiconductor integrated circuit is switchable between (i) a normal mode in which a main signal to be used in a normal operating mode is input as the analog voltage to the pulse modulator, and (ii) a test mode in which at least one internal analog signal generated in the semiconductor integrated circuit is input as the analog voltage to the pulse modulator, and
- wherein the output stage is structured to receive at least one internal digital signal generated by the digital signal processing circuit as its input signal instead of the pulse signal generated by the pulse modulator in the test mode.
An audio amplifier circuit comprising a semiconductor integrated circuit, wherein the semiconductor integrated circuit comprises:
- an output terminal;
- a pulse modulator that receives an analog voltage, and that generates a pulse signal modulated according to the analog voltage;
- and
- an output stage that generates a switching signal at the output terminal according to the pulse signal,
- wherein the semiconductor integrated circuit is switchable between (i) a normal mode in which a main signal to be used in a normal operating mode is input as the analog voltage to the pulse modulator, and (ii) a test mode in which at least one internal analog signal generated in the semiconductor integrated circuit is input as the analog voltage to the pulse modulator,
- wherein the pulse modulator comprises:
- an error amplifier that receives, via an inverting input terminal thereof, the analog voltage and a voltage fed back from the output terminal, and that receives a reference voltage via a non-inverting input terminal thereof;
- and
- a comparator that compares an output voltage of the error amplifier with a cyclic voltage, and that outputs a pulse signal that indicates a comparison result,
- and wherein the output stage comprises a class D amplifier.
Dependencies are inferred from the claim text.