Method of driving an electrical load, and corresponding signal generator and circuit
AssigneeInventronics, Inc.
InventorsFrancesco Angelin, Alessio Griffoni
Life of this patent
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Abstract
A method for driving a unidirectional current through an electrical load, such as one or more LED modules, by applying thereto a PWM-modulated signal that swings between a high value and a low value envisages choosing said high value and said low value as nonzero values having a same sign.
Claims10
A signal generator configured to apply a PWM-modulated voltage signal to an electrical load, the PWM-modulated voltage signal swinging between a high value and a low value, wherein both said high value and said low value are non-zero values having a same sign, the signal generator comprising:
- a first node and a second node configured to have said electrical load coupled therebetween;
- a first de voltage generator arranged intermediate said first node and a ground;
- a second dc voltage generator arranged intermediate said second node and ground or intermediate said second node and said first node;
- a PWM modulator switch intermediate said second node and ground, the PWM modulator switch configured to alternately:
- couple the second node to ground, wherein the high value of the PWM-modulated voltage signal is applied between the first node and the second node from the first de voltage generator,
- decouple the second node from ground, wherein the low value of the PWM-modulated voltage signal is applied between the first node and the second node, wherein the low value of the PWM-modulated voltage signal is a function of:
- the difference of the voltage from the first de voltage generator and the voltage from the second de voltage generator with said second de voltage generator arranged intermediate said second node and ground, or
- the voltage from the second de voltage generator with said second de voltage generator arranged intermediate said second node and said first node.
A circuit configured to apply a PWM-modulated voltage signal to an electrical load by applying thereto the PWM-modulated voltage signal, the PWM-modulated voltage signal swinging between a high value and a low value, wherein both said high value and said low value are non-zero values having a same sign, the circuit comprising a first node and a second node configured to have said electrical load coupled therebetween, wherein the circuit comprises:
- the first node and the second node configured to receive applied therebetween the PWM-modulated voltage signal swinging between a first value and a zero value;
- a series connection of a capacitor and a Zener diode arranged intermediate the first node and the second node, the Zener diode having a Zener voltage and arranged to counter current flow from the second node towards the first node;
- wherein:
- with the first node and the second node receiving applied therebetween said PWM-modulated voltage signal at said first value, said capacitor is charged towards a high value by current flowing through the Zener diode with the first node brought towards said high value;
- and
- with the first node and the second node receiving applied therebetween said PWM-modulated voltage signal at said zero value, the first node is brought towards said low value as a function of the difference of said high value and the Zener voltage of said Zener diode.
Dependencies are inferred from the claim text.