# US 10,871,526 B2 · Apparatus and method for detecting faulty charge pump capacitor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,871,526 B2 - Document ID: US10871526B2 - Status: Granted - Kind: B2 - Application number: 16/237,493 - Filed: 2018-12-31 - Published: 2020-07-02 - Granted: 2020-12-22 - Earliest claimed: 2018-12-31 - Assignees: NXP B.V. - Applicants: NXP B.V. - Inventors: Henricus Cornelis Johannes Büthker - Web page: https://patentgrep.com/patent/US10871526B2 ## CPC - G01R 31/64: Testing of capacitors - H05B 45/44: with an active control inside an LED matrix - F21S 41/141: Light emitting diodes [LED] - G01R 19/16528: {using digital techniques or performing arithmetic operations (using digital techniques to measure a voltage or a current, see G01R19/25)} - H02M 3/07: using capacitors charged and discharged alternately by semiconductor devices with control electrode {, e.g. charge pumps} - H05B 45/37: Converter circuits - B60Q 1/04: the devices being headlights - B60Q 11/005: {for lighting devices, e.g. indicating if lamps are burning or not} - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL - F21S: NON-PORTABLE LIGHTING DEVICES; SYSTEMS THEREOF; VEHICLE LIGHTING DEVICES SPECIALLY ADAPTED FOR VEHICLE EXTERIORS - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - B60Q: ARRANGEMENT OF SIGNALLING OR LIGHTING DEVICES, THE MOUNTING OR SUPPORTING THEREOF OR CIRCUITS THEREFOR, FOR VEHICLES IN GENERAL ## Abstract A light emitting diode (LED) lighting system for an automobile includes a switch block, a capacitor, a charge pump, and a capacitor detector. The charge pump includes an output to provide power to a gate driver of the switch block at a nominal voltage level. The capacitor detector circuit includes a detector input and a detector output. The detector input is connected to the charge pump output and to the charge pump capacitor to detect a voltage level on the charge pump capacitor. The capacitor detector circuit provides a first indication on the detector output that the charge pump capacitor is present and undamaged when the voltage level is greater than the nominal voltage level. The capacitor detector circuit further provides a second indication on the detector output that the charge pump capacitor is not present or is damaged when the voltage level is less than the nominal voltage level. ## Claims ### Claim 1 A light emitting diode (LED) lighting system for an automobile, the LED lighting system comprising: a switch block including a switch element with a drain terminal coupled to a power rail, a source terminal, and a gate terminal coupled to a gate driver; a LED element connected in parallel with the drain and source terminals of the switch element such that the LED element emits light when the gate driver switches the switch element off and such that the LED element does not emit light when the gate driver switches the switch element on, wherein the power rail provides power to the switch block at a first voltage level; a charge pump capacitor; a charge pump coupled to the power rail, the charge pump including a charge pump output connected to a first terminal of the charge pump capacitor, the charge pump output to provide power to the gate driver at a nominal voltage level, the nominal voltage level being greater than the first voltage level, the charge pump further including a charge pump input coupled to the drain terminal and to a second terminal of the charge pump capacitor; and a capacitor detector circuit including a detector input and a detector output, the detector input connected to the charge pump output and to the first terminal of the charge pump capacitor to detect a second voltage level on the charge pump capacitor, the capacitor detector circuit to provide a first indication on the detector output that the charge pump capacitor is present and undamaged when the second voltage level is greater than the nominal voltage level and to provide a second indication on the detector output that the charge pump capacitor is not present or is damaged when the second voltage level is less than the nominal voltage level. ### Claim 2 (depends on 1) The LED lighting system of claim 1, wherein the capacitor detector circuit is further to provide the first indication on the detector output not only when the second voltage level is greater than the nominal voltage level, but also when the second voltage level is greater than a high voltage threshold reference voltage. ### Claim 3 (depends on 2) The LED lighting system of claim 2, wherein the capacitor detector circuit is further to provide the second indication on the detector output not only when the second voltage level is less than the nominal voltage level, but also when the second voltage level is less than a low voltage threshold reference voltage. ### Claim 4 (depends on 3) The LED lighting system of claim 3, wherein the capacitor detector circuit is further to provide the second indication on the detector output not only when the second voltage level is less than the nominal voltage level and when the second voltage level is less than a low voltage level threshold, but also when the second voltage level is less than the low voltage level threshold for longer than a predetermined amount of time, the predetermined amount of time being a non-zero amount of time. ### Claim 5 (depends on 4) The LED lighting system of claim 4, wherein the predetermined amount of time is less than a gate turn-on time of the gate driver. ### Claim 6 (depends on 1) The LED lighting system of claim 1, further comprising: a filter capacitor including a first terminal connected to the second terminal of the charge pump capacitor and a second terminal connected to a ground plane. ### Claim 7 (depends on 6) The LED lighting system of claim 6, wherein in detecting the second voltage level on the charge pump capacitor, the capacitor detector circuit detects a voltage only across the first and second terminals of the charge pump capacitor. ### Claim 8 (depends on 6) The LED lighting system of claim 6, wherein in detecting the second voltage level on the charge pump capacitor, the capacitor detector circuit detects a voltage between the first terminal of the charge pump capacitor and the ground plane. ### Claim 9 (depends on 1) The LED lighting system of claim 1, wherein a slew rate of the gate driver is configurable, and wherein a capacity of the charge pump capacitor is sized based upon the slew rate. ### Claim 10 A method of detecting the presence of a charge pump capacitor in a light emitting diode (LED) lighting system for an automobile, the method comprising: providing, on a switch block of the LED lighting system, a switch element, the switch element including a drain terminal coupled to a power rail, a source terminal, and a gate terminal coupled to a gate driver; a LED element connected in parallel with the drain and source terminals of the switch element such that the LED element emits light when the gate driver switches the switch element off and such that the LED element does not emit light when the gate driver switches the switch element on, wherein the power rail provides power to the switch block at a first voltage level; coupling a charge pump output of a charge pump of the LED lighting system to a first terminal of a charge pump capacitor, the charge pump output to provide power to the gate driver at a nominal voltage level on the charge pump output, the nominal voltage level being greater than the first voltage level; coupling a charge pump input of the charge pump to the drain terminal and to a second terminal of the charge pump capacitor; and coupling a detector input of a capacitor detector circuit of the LED lighting system to the charge pump output and to the first terminal of the charge pump capacitor to detect a second voltage level on the charge pump capacitor providing, on a detector output of the capacitor detector circuit, a first indication on the detector output that the charge pump capacitor is present and undamaged when the second voltage level is greater than the nominal voltage level; and providing, on the detector output, a second indication on the detector output that the charge pump capacitor is not present or is damaged when the second voltage level is less than the nominal voltage level. ### Claim 11 (depends on 10) The method of claim 10, further comprising: providing, by the capacitor detector circuit, the first indication on the detector output not only when the second voltage level is greater than the nominal voltage level, but also when the second voltage level is greater than a high voltage threshold reference voltage. ### Claim 12 (depends on 11) The method of claim 11, further comprising: providing, by the capacitor detector circuit, the second indication on the detector output not only when the second voltage level is less than the nominal voltage level, but also when the second voltage level is less than a low voltage threshold reference voltage. ### Claim 13 (depends on 12) The method of claim 12, further comprising: providing, by the capacitor detector circuit, the second indication on the detector output not only when the second voltage level is less than the nominal voltage level and when the second voltage level is less than a low voltage level threshold, but also when the second voltage level is less than the low voltage level threshold for longer than a predetermined amount of time, the predetermined amount of time being a non-zero amount of time. ### Claim 14 (depends on 13) The method of claim 13, wherein the predetermined amount of time is less than a gate turn-on time of the gate driver. ### Claim 15 (depends on 10) The method of claim 10, further comprising: connecting a first terminal of a filter capacitor of the LED lighting system to the second terminal of the charge pump capacitor; and coupling a second terminal of the filter capacitor to a ground plane. ### Claim 16 (depends on 15) The method of claim 15, wherein in detecting the second voltage level on the charge pump capacitor, the capacitor detector circuit detects a voltage only across the first and second terminals of the charge pump capacitor. ### Claim 17 (depends on 15) The method of claim 15, wherein in detecting the second voltage level on the charge pump capacitor, the capacitor detector circuit detects a voltage between the first terminal of the charge pump capacitor and the ground plane. ### Claim 18 (depends on 10) The method of claim 10, wherein a slew rate of the gate driver is configurable, and wherein a capacity of the charge pump capacitor is sized based upon the slew rate. ### Claim 19 A charge pump system for a light emitting diode (LED) lighting system for an automobile, the charge pump system comprising: a charge pump capacitor; a charge pump coupled to a power rail, the charge pump including a charge pump output connected to a first terminal of the charge pump capacitor, the charge pump output to provide power to a gate driver of a LED element switch block at a nominal voltage level on the charge pump output, the nominal voltage level being greater than a first voltage threshold reference voltage, the charge pump further including a charge pump input coupled to the first terminal and to a second terminal of the charge pump capacitor; and a capacitor detector circuit including a detector input and a detector output, the detector input connected to the charge pump output and to the first terminal of the charge pump capacitor to detect a second voltage level on the charge pump capacitor, the capacitor detector circuit to provide a first indication on the detector output that the charge pump capacitor is present and undamaged when the second voltage level is greater than the nominal voltage level and to provide a second indication on the detector output that the charge pump capacitor is not present or is damaged when the second voltage level is less than the nominal voltage level. ### Claim 20 (depends on 19) The charge pump system of claim 19, wherein the capacitor detector circuit is further to provide the first indication on the detector output not only when the second voltage level is greater than the nominal voltage level, but also when the second voltage level is greater than a high voltage threshold reference voltage, and wherein the capacitor detector circuit is further to provide the second indication on the detector output not only when the second voltage level is less than the nominal voltage level, but also when the second voltage level is less than a low voltage threshold reference voltage.