Motor de Búsqueda de Datasheet de Componentes Electrónicos
 Selected language Spanish  ▼

Delete All
ON OFF
 ALLDATASHEET.ES Part No.DescriptionMarking X

## AN2687 Datasheet(PDF) 8 Page - STMicroelectronics

 No. de Pieza. AN2687 Descripción STM8S20xxx LCD software driver Descarga 22 Pages Scroll/Zoom 100% Fabricante STMICROELECTRONICS [STMicroelectronics] Página de inicio http://www.st.com Logo

## AN2687 Datasheet(HTML) 8 Page - STMicroelectronics

 8 / 22 page LCD drive signalsAN26878/22Doc ID 14296 Rev 1Figure 4.LCD timing diagram for quadruplex mode2.1.1LCD mean voltage calculationThe LCD mean voltage must be very close to zero to guarantee long life to the LCD. TheLCD mean voltage for On and Off periods can be calculated as shown below:Vmean(On) = 1/8 Vseg + 1/8 (–VCOM) + 3(Vseg – Vr/2) + 3(–Vr/2)(1)Vmean(Off) = 3(Vseg/2) + 3(–Vr/2)(2)Vmean(On) and Vmean(Off) assume identical periods for each phase.Equating equations (1) & (2) to zero, that is putting Vmean(On) = 0 and Vmean(Off) = 0,gives:Vseg = VCOM = Vr = VDD, where:●VCOM is the maximum voltage on the COM line●Vr/2 is the voltage in the middle of the resistor bridge, applied on the COM line●Vseg is the maximum voltage on the Segx line●VDD is the microcontroller power supplyCOM1ai15954VCOM+VDD/2COM2Segx_1 OnSegx_2 OffSegx_3 OnSegx_4 OffVseg – VCOMVseg – VCOM1Vseg – VCOM4T/8T/4T/23T/4TCOM3COM4VsegxControlperiodSingle-frame periodLCDCOM1COM2COM3COM4SEG1