Method and system for adding boost functionality to a buck switcher with minimal cost
First Claim
1. A buck (with boost) switcher, comprising:
- an integrated circuit configured to receive a power supply voltage and a mode signal and to generate a boost voltage, a boost current or a buck voltage based on the power supply voltage and the mode signal, the mode signal corresponding to one of a buck mode and a boost mode; and
a single inductor coupled to the integrated circuit and configured to be used by the integrated circuit to generate the boost voltage or the boost current in the boost mode and to generate the buck voltage in the buck mode;
wherein the integrated circuit comprises a maximum voltage selector configured to select one of the power supply voltage and the boost voltage as a maximum voltage for use in operating the switcher, the maximum voltage selector comprising;
a comparator configured to compare the power supply voltage and the boost voltage to generate a comparator output;
a high-voltage transistor coupled to the comparator and configured to select the boost voltage as the maximum voltage when the comparator output indicates that the boost voltage is greater than the power supply voltage; and
a low-voltage transistor coupled to the comparator and configured to select the power supply voltage as the maximum voltage when the comparator output indicates that the power supply voltage is greater than the boost voltage.
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Accused Products
Abstract
A buck (with boost) switcher is provided that adds boost functionality to a buck switcher without compromising the buck'"'"'s performance with extra series-coupled switches nor requiring a second inductor. The switcher has an integrated circuit that is capable of receiving a power supply voltage and a mode signal and generating on separate outputs either a boost voltage or a buck voltage based on the power supply voltage and the mode signal. The mode signal corresponds to one of a buck mode and a boost mode. The switcher also has a single inductor that is coupled to the integrated circuit and is capable of being used by the integrated circuit to generate the boost voltage (or a high voltage capable current) in the boost mode and to generate the buck voltage in the buck mode.
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Citations
20 Claims
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1. A buck (with boost) switcher, comprising:
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an integrated circuit configured to receive a power supply voltage and a mode signal and to generate a boost voltage, a boost current or a buck voltage based on the power supply voltage and the mode signal, the mode signal corresponding to one of a buck mode and a boost mode; and a single inductor coupled to the integrated circuit and configured to be used by the integrated circuit to generate the boost voltage or the boost current in the boost mode and to generate the buck voltage in the buck mode; wherein the integrated circuit comprises a maximum voltage selector configured to select one of the power supply voltage and the boost voltage as a maximum voltage for use in operating the switcher, the maximum voltage selector comprising; a comparator configured to compare the power supply voltage and the boost voltage to generate a comparator output; a high-voltage transistor coupled to the comparator and configured to select the boost voltage as the maximum voltage when the comparator output indicates that the boost voltage is greater than the power supply voltage; and a low-voltage transistor coupled to the comparator and configured to select the power supply voltage as the maximum voltage when the comparator output indicates that the power supply voltage is greater than the boost voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A mobile device, comprising:
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a power supply configured to generate a power supply voltage;
a buck component;
a boost component; and
a buck (with boost) switcher coupled to the power supply, the buck component and the boost component, the switcher configured to (i) operate in one of a buck mode and a boost mode, (ii) generate in the buck mode a buck voltage for the buck component based on the power supply voltage using an inductor, and (iii) generate in the boost mode a boost voltage for the boost component based on the power supply voltage using the inductor;wherein the switcher comprises a maximum voltage selector configured to select one of the power supply voltage and the boost voltage as a maximum voltage for use in operating the switcher, the maximum voltage selector comprising; a comparator configured to compare the power supply voltage and the boost voltage to generate a comparator output; a high-voltage transistor coupled to the comparator and configured to select the boost voltage as the maximum voltage when the comparator output indicates that the boost voltage is greater than the power supply voltage; and a low-voltage transistor coupled to the comparator and configured to select the power supply voltage as the maximum voltage when the comparator output indicates that the power supply voltage is greater than the boost voltage. - View Dependent Claims (11, 12, 13)
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14. A buck (with boost) switcher capable of receiving a
mode signal, the mode signal corresponding to one of a buck mode and a boost mode, the switcher comprising: -
a buck high side transistor configured to be (i) turned on with a specified buck duty cycle when the mode signal corresponds to the buck mode and (ii) turned off when the mode signal corresponds to the boost mode; a boost high side transistor configured to be (i) turned on with a specified boost duty cycle when the mode signal corresponds to the boost mode and (ii) turned off when the mode signal corresponds to the buck mode, and a maximum voltage selector configured to select one of the power supply voltage and the boost voltage as a maximum voltage for use in operating the switcher, the maximum voltage selector comprising; a comparator configured to compare the power supply voltage and the boost voltage to generate a comparator output; a high-voltage transistor coupled to the comparator and configured to select the boost voltage as the maximum voltage when the comparator output indicates that the boost voltage is greater than the power supply voltage; and a low-voltage transistor coupled to the comparator and configured to select the power supply voltage as the maximum voltage when the comparator output indicates that the power supply voltage is greater than the boost voltage. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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Specification