Adaptive switch mode LED driver

US9451664B2 · kind B2 · utility

Assignee

• DIALOG SEMICONDUCTOR INC. · DE

Inventors

• Xuecheng Jin · Palo Alto, US
• Yu-Cheng Chang · Taipei, TW
• Yang Li · Santa Clara, US
• Maofeng Lan · Palo Alto, US
• John William Kesterson · Monterey, US
• Xiaoyan Wang · Milpitas, US
• Chenghung Pan · Palo Alto, US

Key dates

• Filing date: Nov 13, 2012
• Grant date: Sep 20, 2016
• Expiry date: Nov 13, 2032

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02B20/30
• WIPO field: Electrical machinery, apparatus, energy
• WIPO sector: Electrical engineering

Abstract

An adaptive switch mode LED driver provides an intelligent approach to driving multiple strings of LEDs. The LED driver determines an optimal current level for each LED channel from a limited set of allowed currents. The LDO driver then determines a PWM duty cycle for driving the LEDs in each LED channel to provide precise brightness control over the LED channels. Beneficially, the LED driver minimizes the power dissipation in the LDO circuits driving each LED string, while also ensuring that the currents in each LED string are maintained within a limited range. A sample and hold LDO allows PWM control over extreme duty cycles with very fast dynamic response. Furthermore, fault protection circuitry ensures fault-free startup and operation of the LED driver.