Technical Q&A

Q.	Why I can't see any data on the LCD?
A.	Please fellow the spec; use a POT to adjust the VEE ( VO ) voltage to turn on the LCD.

Q.	How to turn on the 4.5 volt LCD with the 3-volt VDD?
A.	You need provide -1.5 volt to the VO. We recommend you to use a D to -DC voltage converter IC, such as SCI7661, HT7660 or equivalent if you haven't a -1.5 volt on your power system.

How to turn on the LED back light?

Please check the spec with the LED forward voltage and current. Generally, one LED forward voltage is 2.05 V and current is 10 mA. For the 3-volt power system, there are many LED arranged in parallel. For the 5-volt power system, 2 LED arranged in a string, it forward voltage is 4.1 volt; current is 10 mA and many in parallel. Both LED back light, need current limit resistor either on our board or yours, for drop your system power to meet LED forward current spec.

Q.	How to turn on the E.L panel back light?
A.	To turn on an E.L panel, typically need about 100 Vrms @ 400 HZ and it current consumption is about 0.12 mA per CM square. The E.L drive IC that we often use and recommend is IMP and SIPEX.

Q.	How to turn on the CCFL back light?
A.	The CCFL input power spec is about 600 Vrms, 35K HZ and 5 mA. The inverter we recommend is TDK CXA-L10A or equivalent. Caution: This is high voltage device. Please avoid electric shock.