Power supply circuit and electronic appliance therewith
First Claim
1. A power supply circuit comprising:
- a first current control portion that controls, at a predetermined current level, currents fed from a power supply portion to a plurality of LEDs connected in parallel with one another;
a first current setting portion that sets, in the first current control portion, a level of currents to be passed through the LEDs; and
a checking portion that checks whether currents at the current level set by the first current setting portion can be passed through the LEDs;
wherein when the checking portion recognizes a condition in which at least one of the LEDs cannot be fed with a current at the level set by the first current setting portion, the checking portion feeds the first current setting portion a signal indicating the condition, and on receiving the signal, the first current setting portion changes the currently set current level to a current level at which currents can be passed through all the LEDs.
1 Assignment
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Accused Products
Abstract
A power supply circuit (10) has a current control portion (5) that controls, at a predetermined level, the currents passed through LEDs (3) and (4); a current setting portion (6) that sets, in the current control portion (5), the level of currents to be passed through the LEDs (3) and (4); and a checking portion (7) that checks whether or not currents at the current level set by the current setting portion (6) can be passed through the LEDs (3) and (4). The checking portion (7), on recognizing a condition in which at least one of the LEDs (3) and (4) cannot be fed with a current at the level set by the current setting portion (6), feeds the current setting portion (6) with a signal indicating the condition; on receiving the signal, the current setting portion (6) changes the currently set current level to a current level at which currents can be passed through both the LEDs (3) and (4). This helps realize an LED driving power supply circuit that, despite having a small circuit scale, tolerates a wide range for the supplied voltage.
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Citations
16 Claims
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1. A power supply circuit comprising:
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a first current control portion that controls, at a predetermined current level, currents fed from a power supply portion to a plurality of LEDs connected in parallel with one another;
a first current setting portion that sets, in the first current control portion, a level of currents to be passed through the LEDs; and
a checking portion that checks whether currents at the current level set by the first current setting portion can be passed through the LEDs;
wherein when the checking portion recognizes a condition in which at least one of the LEDs cannot be fed with a current at the level set by the first current setting portion, the checking portion feeds the first current setting portion a signal indicating the condition, and on receiving the signal, the first current setting portion changes the currently set current level to a current level at which currents can be passed through all the LEDs. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification