Flash driver to limit a load current of a flash and method to limit a load current of a flash driver
First Claim
1. A flash driver to limit a load current for a flash comprising:
- a dc/dc converter having a first input to receive an input voltage and an output to supply an output voltage, and being designed to convert the input voltage to the output voltage;
an adjustable current source connected between the output and a load terminal;
a first control unit connected to the first input and coupled to the adjustable current source, and being designed to compare the input voltage to a threshold and, if the comparison indicates the input voltage being smaller than the threshold value, adjust the adjustable current source such that the input voltage is equal or greater than the threshold value; and
a second control unit coupled to the adjustable current source and the dc/dc converter to detect a voltage drop over the adjustable current source and to set the dc/dc converter to control the conversion of input voltage to the output voltage depending on the detected voltage drop.
1 Assignment
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Accused Products
Abstract
A flash driver to limit a load current for a flash comprises a dc/dc converter (DCDC) having a first input (IN1) to receive an input voltage (Vin) and an output (OUT) to supply an output voltage (Vout). The dc/dc converter is designed to convert the input voltage (Vin) to the output voltage (Vout). Furthermore the flash driver has an adjustable current source (Iadj) connected between the output (OUT) and a load terminal (LT). A first control unit (CTRL—1) is connected to the first input (IN1) and coupled to the adjustable current source (Iadj), and is designed to compare the input voltage (Vin) to a threshold (Vth) and, if the comparison indicates the input voltage (Vin) being smaller than the threshold value (Vth), adjust the adjustable current source (Iadj) such that the input voltage (Vin) is equal or greater than the threshold value (Vth). A second control unit (CTRL—2) is coupled to the adjustable current source (Iadj) and the dc/dc converter (DCDC) and is designed to detect a voltage drop over the adjustable current source (Iadj) and to set the dc/dc converter (DCDC) to control the conversion of input voltage (Vin) to the output voltage (Vout) depending on the detected voltage drop.
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Citations
16 Claims
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1. A flash driver to limit a load current for a flash comprising:
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a dc/dc converter having a first input to receive an input voltage and an output to supply an output voltage, and being designed to convert the input voltage to the output voltage; an adjustable current source connected between the output and a load terminal; a first control unit connected to the first input and coupled to the adjustable current source, and being designed to compare the input voltage to a threshold and, if the comparison indicates the input voltage being smaller than the threshold value, adjust the adjustable current source such that the input voltage is equal or greater than the threshold value; and a second control unit coupled to the adjustable current source and the dc/dc converter to detect a voltage drop over the adjustable current source and to set the dc/dc converter to control the conversion of input voltage to the output voltage depending on the detected voltage drop. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method to limit a load current for a flash driver, comprising the steps of:
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receiving an input voltage; converting the input voltage to an output voltage using a dc/dc converter; providing a load current depending on the input voltage and a respective load by using an adjustable current source; comparing the input voltage to a threshold value and, if the comparison indicates the input voltage being smaller than the threshold value adjust the adjustable current source until the input voltage is equal or greater than the threshold value; and determining from the so adjusted adjustable current source a voltage drop over the adjustable current source and set the dc/dc converter to control the converting of the input voltage to the output voltage depending on the determined voltage drop. - View Dependent Claims (14, 15, 16)
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Specification