Single Pin Sensing for LED Driver Standby Drain
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Solution Overview
Problem
Existing operating devices for light sources with actively switched converters suffer from current drain during standby mode, leading to battery discharge and increased dimensions and costs due to multiple pins for parameter measurement.
Innovation Solution
An operating device with a single sensing pin using a capacitive shunt for closed-loop control, eliminating resistive shunts and reducing the number of pins needed for current, voltage, and zero-crossing detection, thereby minimizing energy consumption and device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate pins and ohmic measurement units are used for each electrical parameter (current, voltage, zero crossing), then measurement precision is improved, but device complexity and dimensions increase
Solution Approach 1:
The patent combines multiple measurement functions (current detection, voltage detection, zero crossing detection) into a single pin of the control unit. The capacitive shunt circuit connected to this single pin enables the control unit to derive all necessary electrical parameters through signal processing, eliminating the need for separate pins and measurement units for each parameter.
Solution Approach 2:
The single pin of the control unit serves multiple functions: it detects current through the capacitive shunt during switching operations, measures voltage across the light source, and identifies zero crossing points of the current. This multi-functional approach reduces the number of required pins while maintaining comprehensive electrical parameter monitoring.
2Measurement precision
If ohmic measurement units (voltage dividers with resistors) are used for measuring electrical parameters, then measurement precision is improved, but energy consumption increases during standby mode
Solution Approach 1:
The patent changes the fundamental parameter of the measurement circuit from resistive to capacitive. The capacitive shunt uses capacitors instead of resistors, which fundamentally alters the energy consumption characteristics. Capacitors do not consume power in standby mode unlike resistors, thereby eliminating continuous current drain while maintaining measurement capability.
Solution Approach 2:
The patent extracts the resistive elements (ohmic resistors in voltage dividers) from the measurement circuit and replaces them with capacitive elements. This extraction of the harmful resistive component eliminates the continuous power consumption associated with ohmic measurement units during standby mode.
3Measurement precision
If multiple separate measurement units are used for current, voltage and zero crossing detection, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent merges multiple separate measurement units into a single integrated capacitive shunt circuit. This consolidation reduces the number of discrete components (resistors, separate measurement circuits) that need to be manufactured and assembled, thereby reducing manufacturing complexity and cost while maintaining measurement precision through the unified capacitive approach.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances efficiency without increasing costs, preventing battery discharge during standby mode and reducing the device's dimensions by using a capacitive shunt for closed-loop control in a boost or flyback converter.
Implementation Method 1
the control unit comprises a single sensing pin for being supplied with a signal representing: the value of the current flowing through the first switch when the first switch is controlled in the conducting state; the value of the voltage across the at least one light source
Implementation Method 2
The at least one converter comprises a first switch, preferably transistor, and an energy storage (L1), preferably inductor, which are electrically connected in series
Data Source
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AI summary
The present invention relates to an operating device (1) for supplying at least one light source (4), preferably at least one LED, with electrical energy; wherein the operating device (1) comprises at least one input terminal (IN, IN') for electrically connecting an electrical energy source (B1), preferably a battery, configured to supply electrical energy to the operating device (1); at least one output terminal (OUT, OUT') for electrically connecting the at least one light source (4) to the operating device (1); at least one actively switched converter (2), preferably a boost convert or a flyback converter, electrically connected with the at least one input terminal (IN, IN') and the at least one output terminal (OUT, OUT') of the operating device (1); and a control unit (3), preferably an ASIC. The at least one converter (2) comprises a first switch (Q1), preferably transistor, and an energy storage (L1), preferably inductor, which are electrically connected in series; and the control unit (3) is configured to control the switching of the first switch (Q1) in order to control the charging and discharging of the energy storage (L1) and, thus, the voltage, current and/or electrical energy output by the converter (2). The control unit (3) comprises a single sensing pin (P) for being supplied with a signal representing: the value of the current (IQ1) flowing through the first switch (Q1) when the first switch (Q1) is controlled in the conducting state; the value of the voltage (V4) across the at least one light source (4) when the at least one light source (4) is electrically connected to the at least one output terminal (OUT, OUT') of the operating device (1); and the point in time of the zero crossing of the current (IL1) through the energy storage (L1). The present invention also relates to a lamp comprising at least one operating device according to the invention; and to a method for controlling an operating device.