Low-cost LCD-bias generator uses main microcontroller as control IC

摘要

LCD circuits often require a - 10V voltage at 2 to 15 mA to bias a graphics-LCD-driver IC. You can usually accomplish this task with an external charge-pump IC, such as Maxim's ICL7660, but that approach adds cost to the design. Instead, you can control a buck-boost switch-mode regulator using the same microcontroller that sends data to the LCD. In addition, you can sequence the power rails under software control, as some types of LCI) controllers require.