Bootstrap startup and assist circuit

• US 9,041,379 B2
• Filed: 09/10/2010
• Issued: 05/26/2015
• Est. Priority Date: 09/10/2009
• Status: Active Grant

• Current Assignee: Mate, LLC
• Original Assignee: Lumastream Canada Ulc
• Inventors: Lyons, Steven
• Primary Examiner(s): Laxton, Gary L
• Application Number:
  US13/382,721
• Publication Number:
  US 20120262144A1
• Time in Patent Office: 1,719 Days
• Field of Search: 363/49, 323/901, 323/288
• US Class Current: 323/288
• CPC Class Codes: H05B 45/355 Power factor correction [PFC]; Reactive power compensation
• CPC Class Codes: H05B 45/3725 Switched mode power supply [SMPS]
• CPC Class Codes: H05B 45/38 using boost topology
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
• CPC Class Codes: Y10S 323/901 Starting circuits

Abstract

A bootstrap assist circuit and a startup circuit comprising a voltage controlled switch and a startup ramp voltage generator connected to the voltage controlled switch that will control a high side switch, a dimming interface or an enable/disable input function. Said system is used to provide a bootstrap technique to continuously switch a floating high side switch (MOSFET) by continuously charging a capacitor and then “level shifting” said capacitor voltage across the gate and source of the said high side switch to turn the switch on.

Claims

1. A method of bootstrap startup comprising:

receiving an input signal to begin bootstrapping;

initiating a startup voltage ramp;

initiating an artificial ramp current sense;

determining if a voltage controlled switch is reverse-biased; and

terminating the artificial ramp current sense if the voltage controlled switch is reverse-biased.

2. The method of claim 1 wherein if the voltage controlled switch is not reverse-biased, repeating initiating the artificial ramp current sense and determining if the voltage controlled switch is reverse-biased until it is determined that the voltage controlled switch is reverse-biased.

3. The method of claim 1 wherein initiating a startup voltage ramp comprises:

transmitting a current through an RC time constant.

4. The method of claim 1 wherein initiating the artificial ramp current sense comprises:

turning on a gate drive signal from a power factor corrected (PFC) transition mode (TM) control.

5. The method of claim 1 wherein initiating the artificial ramp current sense comprises:

detecting a voltage at a current sense pin within a power factor corrected (PFC) transition mode (TM) control.

6. The method of claim 1 wherein initiating the artificial ramp current sense comprises:

detecting a signal at a zero current detector within a power factor corrected (PFC) transition mode (TM) control.

7. The method of claim 1 wherein initiating an artificial ramp current sense comprises:

coupling a gate drive signal of a power factor corrected (PFC) transition mode (TM) control with a current sense of the PFC TM control.