參數(shù)資料
型號(hào): AK4533
廠商: Asahi Kasei Microsystems Co.,Ltd
元件分類: Codec
英文描述: Audio Codec with Touch Screen Controller
中文描述: 音頻編解碼器與觸摸屏控制器
文件頁(yè)數(shù): 29/40頁(yè)
文件大小: 473K
代理商: AK4533
[ASAHI KASEI]
<Revision 0.9a>
July 00
28
A/D Converter for Touch Screen
The AK4533 has 12 bit resolution Successive Approximation Resistor (SAR) A/D converter for touch screen, and the
measurement of buttery voltage.
As A/D converter uses capacitive redistribution architecture, internal capacitors also operate as sample/hold circuit.
TSY_TOP pin or TSX_TOP pin, which is used for detecting the pressed position, is selected as analog input to ADC.
VA is referred to as full scale of ADC. When BTI_1 pin, or BTI_2 pin is selected for the measurement of buttery
voltage as analog input to A/D converter, TPVREFIN is referred to as full scale of ADC.
Tracking time, which is defined as the time to store the charge into internal capacitors, depends on the output
impedance (Rin) of touch screen. If Rin is 500
, at least 1.5
μ
s is required for tracking time. The AK4533 uses 3
TADCK cycles for tracking: If TADCK is 2MHz, tracking time is 0.5
μ
s * 3 cycles = 1.5
μ
s. If Rin is larger value at the
measurement of buttery voltage, not only enough tracking time is required, but also the clock frequency of TADCK
should be lower than 2MHz.
Data format of Touch Screen A/D converter is binary as Table 6.
Input Voltage
(VREF-1.5LSB) - VREF
(VREF-2.5LSB) - (VREF-1.5LSB)
---------
0.5LSB - 1.5LSB
0 - 0.5LSB
VREF : VA or TPVREFIN
Output Code
FFF
FFE
---------
001
000
Table 6. Data format
Figure 17 shows the touch screen controller block, and the connection between touch screen and the AK4533. Two
times of A/D conversion is needed to detect the pressed position: one is for X-axis, and another is for Y-axis. A pair of
terminals of touch screen is biased while another terminal is hi-Z state. ADC measures the voltage that is induced to
TOP side of hi-Z terminals. For example, if TSX_TOP and TSX BTM are biased to VA, and AGND respectively, the
ADC can output the dot on X-axis by measuring TSY_TOP voltage.
TSY_BTM
TSX_BTM
TSY_TOP
TSX_TOP
12bit
ADC
(SAR type)
BTI_1
INT
TADCK
TADRDY
TADOUT
VRE F
AIN
Touch
Screen
Battery1
Battery2
BTI_2
TPVREFIN
TADE
Control
Logic
SCLK
CS
SDTI
SDTO
VA
PW
Figure 17. Connection between AK4533 and Touch Screen
相關(guān)PDF資料
PDF描述
AK4534 16Bit CODEC with MIC/HP/SPK-AMP
AK4534VN 16Bit CODEC with MIC/HP/SPK-AMP
AK4536 16-Bit Mono CODEC with ALC & MIC/SPK-AMP
AK4536VN 16-Bit Mono CODEC with ALC & MIC/SPK-AMP
AK4537 16-Bit ツヒ Stereo CODEC with MIC/HP/SPK-AMP
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
AK4534 制造商:AKM 制造商全稱:AKM 功能描述:16Bit CODEC with MIC/HP/SPK-AMP
AK4534VN 制造商:AKM 制造商全稱:AKM 功能描述:16Bit CODEC with MIC/HP/SPK-AMP
AK4534VQ 功能描述:IC CODEC 16BIT MIC/HP/SPK-AMP 制造商:akm semiconductor inc. 系列:* 零件狀態(tài):上次購(gòu)買時(shí)間 標(biāo)準(zhǔn)包裝:1,000
AK4536 制造商:AKM 制造商全稱:AKM 功能描述:16-Bit Mono CODEC with ALC & MIC/SPK-AMP
AK4536VN 制造商:AKM 制造商全稱:AKM 功能描述:16-Bit Mono CODEC with ALC & MIC/SPK-AMP