Method and apparatus providing final test and trimming for a power supply controller
First Claim
1. A method, comprising:
- packaging an integrated circuit die including a switched mode power supply controller;
trimming permanently a parameter of the switched mode power supply controller after packaging the integrated circuit die including the switched mode power supply controller, wherein any reprogramming of the parameter is not possible once it is permanently trimmed;
switching a power switch in response to a control circuit included in the switched mode power supply controller; and
transferring energy from an input of a power supply controlled by the switched mode power supply controller to an output of the power supply in response to the switching of the power switch.
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Abstract
A power supply controller having final test and trim circuitry. In one embodiment, a power supply controller for switched mode power supply includes a selector circuit, a trim circuit, a shutdown circuit and a disable circuit. The trim circuit includes a programmable circuit connection that can be selected by the selector circuit by toggling a voltage on an external terminal such as for example a power supply terminal, a control terminal or a function terminal of the power supply controller. The programmable circuit connection in the trim circuit can be programmed by applying a programming voltage to the external terminal. The shutdown circuit shuts down the power supply controller if the temperature rises above an over temperature threshold voltage. The shutdown circuit includes adjustment circuitry that can be used to test the shutdown circuit. The adjustment circuitry can adjust and reduce the over temperature threshold of the power supply controller. Thus, the power supply controller can be tested without having to actually heat the part. The disable circuit includes a programmable circuit connection, which when programmed prevents further trimming of power supply controller and prevents adjustment of the shutdown circuit over temperature threshold.
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Citations
5 Claims
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1. A method, comprising:
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packaging an integrated circuit die including a switched mode power supply controller;
trimming permanently a parameter of the switched mode power supply controller after packaging the integrated circuit die including the switched mode power supply controller, wherein any reprogramming of the parameter is not possible once it is permanently trimmed;
switching a power switch in response to a control circuit included in the switched mode power supply controller; and
transferring energy from an input of a power supply controlled by the switched mode power supply controller to an output of the power supply in response to the switching of the power switch. - View Dependent Claims (2, 3, 4, 5)
selecting a first trim circuit of the switched mode power supply controller with an external terminal of the switched mode power supply controller, wherein the external terminal is one of a power supply terminal, a control terminal and a function terminal of the switched mode power supply controller; and
applying a programming voltage to the external terminal after selecting the first trim circuit to program a first programmable circuit connection of the first trim circuit.
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3. The method of claim 2 further comprising verifying that the first programmable circuit connection is programmed.
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4. The method of claim 3 wherein verifying that the first programmable circuit connection is programmed comprises:
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measuring a power supply current of the switched mode power supply controller before applying the programming voltage to the external terminal; and
measuring the power supply current of the switched mode power supply controller after applying the programming voltage to the external terminal.
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5. The method of claim 3 wherein verifying that the first programmable circuit connection is programmed comprises:
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selecting the first trim circuit of the switched mode power supply controller with the external terminal of the switched mode power supply controller; and
measuring a power supply current of the switched mode power supply controller.
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Specification