Controller for switching regulator, switching regulator and light source
AssigneeDiodes Zetex Semiconductors Limited
InventorsRohit Arora, Alan James Dodd, Craig Maurice Taylor
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Abstract
A switching regulator (2-5) supplies a controllable stable average current to a load (1), such as series-connected light emitting diodes. A regulator controller (2) includes a hysteretic comparator (12, 30) which controls a switch in the form of a transistor (15) for switching current into an inductor (3). The comparator (12) has upper and lower thresholds. A first circuit comprising a fast current monitor (6) supplies a first signal to the comparator representing the instantaneous current in the inductor (3). A second circuit (36, 37, 41, and 42) supplies a second signal to the comparator representing an error between a desired regulator output and an actual regulator output.
Claims15
A controller for a switching regulator, comprising:
- a hysteretic comparator (12, 30) for controlling a switch (15) for switching current into an inductor (3), the comparator (12, 30) having upper and lower thresholds;
- and a first circuit (6, 9) for supplying a first signal, representing instantaneous current in the inductor (3), to the comparator (12, 30), characterised by comprising a second circuit (36, 37, 41, 42) for supplying a second signal to the comparator, representing an error between a desired regulator output and an actual regulator output.
The regulator as claimed in 11, characterised in that the first sensing resistor (5) is connected to the second circuit (36, 37, 41, 42).
Dependencies are inferred from the claim text.