# US 2014/0152275 A1 · Bootstrap Capacitor Detecting Circuit and Bootstrap DC-DC Converter Thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152275 A1 - Document ID: US20140152275A1 - Status: Published application - Kind: A1 - Application number: 13/745,864 - Filed: 2013-01-21 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Anpec Electronics Corporation - Applicants: Anpec Electronics Corporation - Inventors: Tsung-Kuan Lee; Chih-Yuan Chen - Web page: https://patentgrep.com/patent/US20140152275A1 ## CPC - G05F 1/468: {characterised by reference voltage circuitry, e.g. soft start, remote shutdown} - H02M 3/158: including plural semiconductor devices as final control devices for a single load - H02M 1/0006: {Arrangements for supplying an adequate voltage to the control circuit of converters} - H02M 1/08: Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters - G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES - 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) ## Abstract A bootstrap capacitor detecting circuit includes a current source, for providing a discharging current; a first switch, for conducting connection between a system voltage and a bootstrap voltage node according to a power-on-reset signal, to charge the bootstrap voltage node; a second switch, for conducting connection between a current source and the bootstrap voltage node according to the power-on-reset signal, to discharge the bootstrap voltage node; and a detecting unit, for determining whether a bootstrap capacitor is connected normally according to a bootstrap voltage of the bootstrap voltage node after the current source discharges the bootstrap voltage node. ## Claims ### Claim 1 A bootstrap capacitor detecting circuit for a bootstrap DC-DC converter, comprising: a current source, for providing a discharging current; a first switch, coupled between a system voltage and a bootstrap voltage node, for conducting connection between the system voltage and the bootstrap voltage node according to a power-on-reset signal, to charge the bootstrap voltage node; a second switch, coupled between the current source and the bootstrap voltage node, for conducting connection between the current source and the bootstrap voltage node according to the power-on-reset signal, to discharge the bootstrap voltage node; and a detecting unit, for determining whether a bootstrap capacitor is connected normally according to a bootstrap voltage of the bootstrap voltage node after the current source discharges the bootstrap voltage node. ### Claim 2 (depends on 1) The bootstrap capacitor detecting circuit of claim 1, wherein the discharging current is much less than a capacity of the bootstrap capacitor. ### Claim 3 (depends on 1) The bootstrap capacitor detecting circuit of claim 1, wherein the bootstrap voltage node is coupled to an input terminal of a driving voltage of an upper gate driving unit. ### Claim 4 (depends on 1) The bootstrap capacitor detecting circuit of claim 1, wherein the first switch conducts the connection between the system voltage and the bootstrap voltage node to charge the bootstrap voltage node, and the second switch cuts off the connection between the current source and the bootstrap voltage node before the power-on-reset signal changes a state. ### Claim 5 (depends on 1) The bootstrap capacitor detecting circuit of claim 1, wherein the first switch cuts off the connection between the system voltage and the bootstrap voltage node to stop charging the bootstrap voltage node, and the second switch conducts the connection between the current source and the bootstrap voltage node to discharge the bootstrap voltage node during a specific period after the power-on-reset signal changes a state. ### Claim 6 (depends on 5) The bootstrap capacitor detecting circuit of claim 5, wherein the detecting unit determines whether a bootstrap capacitor is connected normally according to a bootstrap voltage before an end of the specific period. ### Claim 7 (depends on 6) The bootstrap capacitor detecting circuit of claim 6, wherein the detecting unit determines the bootstrap capacitor is not connected normally if the bootstrap voltage is less than a reference voltage and determines the bootstrap capacitor is connected normally if the bootstrap voltage is greater than the reference voltage. ### Claim 8 (depends on 1) The bootstrap capacitor detecting circuit of claim 1, wherein the detecting unit comprises: a comparator, comprising an input terminal coupled to the bootstrap voltage node and another input terminal coupled to a reference voltage for outputting a comparison result; and a latch, for generating a latch signal to indicate whether a bootstrap capacitor is connected normally according to the comparison result. ### Claim 9 A bootstrap DC-DC converter, comprising: a bootstrap capacitor; an upper gate driving unit, comprising an input terminal of a driving voltage coupled to a bootstrap voltage node; and a bootstrap capacitor detecting circuit, comprising: a current source, for providing a discharging current; a first switch, coupled between a system voltage and a bootstrap voltage node, for conducting connection between the system voltage and the bootstrap voltage node according to a power-on-reset signal, to charge the bootstrap voltage node; a second switch, coupled between the current source and the bootstrap voltage node, for conducting connection between the current source and the bootstrap voltage node according to the power-on-reset signal, to discharge the bootstrap voltage node; and a detecting unit, for determining whether a bootstrap capacitor is connected normally according to a bootstrap voltage of the bootstrap voltage node after the current source discharges the bootstrap voltage node. ### Claim 10 (depends on 9) The bootstrap DC-DC converter of claim 9, wherein the discharging current is much less than a capacity of the bootstrap capacitor. ### Claim 11 (depends on 9) The bootstrap DC-DC converter of claim 9, wherein the first switch conducts the connection between the system voltage and the bootstrap voltage node to charge the bootstrap voltage node, and the second switch cuts off the connection between the current source and the bootstrap voltage node before the power-on-reset signal changes a state. ### Claim 12 (depends on 9) The bootstrap DC-DC converter of claim 9, wherein the first switch cuts off the connection between the system voltage and the bootstrap voltage node to stop charging the bootstrap voltage node, and the second switch conducts the connection between the current source and the bootstrap voltage node to discharge the bootstrap voltage node during a specific period after the power-on-reset signal changes a state. ### Claim 13 (depends on 12) The bootstrap DC-DC converter of claim 12, wherein the detecting unit determines whether a bootstrap capacitor is connected normally according to a bootstrap voltage before an end of the specific period. ### Claim 14 (depends on 13) The bootstrap DC-DC converter of claim 13, wherein the detecting unit determines the bootstrap capacitor is not connected normally if the bootstrap voltage is less than a reference voltage and determines the bootstrap capacitor is connected normally if the bootstrap voltage is greater than the reference voltage. ### Claim 15 (depends on 9) The bootstrap DC-DC converter of claim 9, wherein the detecting unit comprises: a comparator, comprising an input terminal coupled to the bootstrap voltage node and another input terminal coupled to a reference voltage for outputting a comparison result; and a latch, for generating a latch signal to indicate whether a bootstrap capacitor is connected normally according to the comparison result.