Epson Research and Development Page 21Vancouver Design CenterS5U13706B00C Rev. 1.0 Evaluation Board User Manual S1D13706Issue Date: 01/02/23 X31B-G-004-04The S5U13706B00C uses GPO and CVOUT to control the MAX754 as shown in thefollowing table..When JP5 is set to position 2-3, VDDH is adjustable using R24 (200Ω potentiometer) toprovide an output voltage from +24V to +40V.NoteWhen manually adjusting the voltage, set the potentiometer according to the panel’sspecific power requirements before connecting the panel.6.5 Manual/Software Adjustable LCD Panel Negative Power Supply (VLCD)Most passive monochrome LCD panels require a negative bias voltage between -14V and-24V. The S5U13706B00C uses a Maxim MAX749 Digitally Adjustable LCD Bias Supplyto provide this voltage range. The signal VLCD can be adjusted manually (using a potenti-ometer) or controlled through software.When JP7 is set to position 1-2, VLCD can be controlled through software to provide anoutput voltage from -8V to -24V. CVOUT and GPO of the S1D13706 are connected to ADJand CTRL of MAX749. The output voltage (VLCD) can be adjusted from -8V to -24V in64 steps by sending pulses to CVOUT. Each CVOUT pulse increments VLCD one steptowards -24V. When decremented beyond -24V, VLCD resets to -8V again. In other words,63 pulses equal incrementing 1 step. After the MAX749 is reset (see “Controlling theMAX749” on page 21), VLCD is set at -16V.The S5U13706B00C uses GPO and CVOUT to control the MAX749 as shown in thefollowing table..When jumper JP7 is set to position 2-3, VLCD can be adjusted by R41 (500K potenti-ometer) to provide an output voltage from -16V to -23V.NoteWhen using manual adjust, set the potentiometer according to the panel’s specific powerrequirements before connecting the panel.Table 6-1: Controlling the MAX754Signal Turn MAX754 On Turn MAX754 Off Reset MAX754GPO high low lowCVOUT X low highX = don’t careTable 6-2: Controlling the MAX749Signal Turn MAX749 On Turn MAX749 Off Reset MAX749GPO high low lowCVOUT X low highX = don’t care
