今天小编要和大家分享的是MAX16820相关信息,接下来我将从MAX16820典型应用电路图,max16820 pdf datasheet浏览和下载这几个方面来介绍。
MAX16820相关技术文章MAX16820典型应用电路图
For several LEDs in series, the sum of their VF voltages can go to 40V or more, and if not referenced to ground, that VF sum requires a differential measurement. As a third challenge (in addition to high voltage and differential measurement), HBLEDs are often dimmed using pulse-width modulation (PWM). If so, you can't measure VF during the low portion of the PWM duty cycle, when the LEDs are not illuminated and VF is not present. For a hysteretic buck LED driver (MAX16820) driving three LEDs in series (Figure 1), you must measure the anode and cathode voltages of the string when DIM is high.Figure 1. Standard driver circuit for HB LEDs.To avoid the need for a differential high-voltage measurement, you can take the indirect approach of measuring the duty cycle at the DRV pin. For this particular LED driver, a first-order estimate of forward voltage for the LED string is VF = D × VIN, where D represents an internal duty cycle produced in the IC's switchmode section (not to be confused with the duty cycle at DIM). The DRV signal is referenced to ground and limited to VCC (5V). That condition allows the use of low voltage ADCs or comparators, which in turn can be powered by the LED driver's VCC output (10mA maximum).关于MAX16820就介绍完了,您有什么想法可以联系小编。