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| 型号： | TC7135CLI |
| 厂商： | Microchip Technology |
| 文件页数： | 6/28页 |
| 文件大小： | 0K |
| 描述： | IC ADC 4 1/2DGT 28-PLCC |
| 标准包装： | 39 |
| 显示器类型： | LED |
| 配置： | 7 段显示 |
| 接口： | BCD |
| 数字或字符： | A/D，4.5 位数字 |
| 电流 - 电源： | 1mA |
| 电源电压： | 4 V ~ 6 V |
| 工作温度： | 0°C ~ 70°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 28-LCC（J 形引线） |
| 供应商设备封装： | 28-PLCC |
| 包装： | 管件 |
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TC7135
3.0
DETAILED DESCRIPTION
The dual-slope converter accuracy is unrelated to the
integrating resistor and capacitor values, as long as
All pin designations refer to the 28-pin PDIP package.
they are stable during a measurement cycle. An
inherent benefit is noise immunity. Noise spikes are
3.1
Dual-Slope Conversion Principles
integrated, or averaged, to zero during the integration
The TC7135 is a dual-slope, integrating A/D converter.
An understanding of the dual-slope conversion
technique will aid in following the detailed TC7135
operational theory.
The conventional dual-slope converter measurement
periods.
Integrated ADCs are immune to the large conversion
errors that plague successive approximation converters
in high-noise environments (see Figure 3-1 ).
cycle has two distinct phases:
1. Input signal integration.
2. Reference voltage integration (de-integration).
The input signal being converted is integrated for a
Analog Input
Signal
Integrator
-
+
Comparator
-
+
fixed time period. Time is measured by counting clock
pulses. An opposite polarity constant reference voltage
is then integrated until the integrator output voltage
returns to zero. The reference integration time is
directly proportional to the input signal.
REF
Voltage
Switch
Drive
Polarity Control
Phase
Control
Control
Logic
Clock
In a simple dual-slope converter, a complete
conversion requires the integrator output to “ramp-up”
and “ramp-down”.
A simple mathematical equation relates the input
signal, reference voltage and integration time:
Fixed
Display
Variable
V IN
V IN
≈ V REF
≈ 1/2 V REF
Counter
EQUATION 3-1:
Signal
Integrate
Reference
Integrate
R INT C INT ∫ 0
------------------------ INT V IN ( T ) DT = --------------------------------
1 T V REF T DEINT
R INT C INT
Time Time
FIGURE 3-1:
Basic Dual-Slope Converter.
Where:
3.2
Operational Theory
V REF
T INT
T DEINT
=
=
=
Reference voltage
Signal integration time (fixed)
Reference voltage integration time
(variable)
The TC7135 incorporates a system zero phase and
integrator output voltage zero phase to the normal two-
phase dual-slope measurement cycle. Reduced
system errors, fewer calibration steps and a shorter
overrange recovery time result.
For a constant V IN :
The TC7135 measurement cycle contains four phases:
EQUATION 3-2:
V REF T DEINT
V IN = --------------------------------
T INT
1.
2.
3.
4.
System zero.
Analog input signal integration.
Reference voltage integration.
Integrator output zero.
Internal analog gate status for each phase is shown in
TABLE 3-1:
INTERNAL ANALOG GATE STATUS
Conversion Cycle Phase
System Zero
Input Signal Integration
Reference Voltage Integration
Integrator Output Zero
SW I
—
Closed
—
—
SW RI +
—
—
Closed *
—
SW RI -
—
—
—
—
SW Z
Closed
—
—
—
SW R
Closed
—
—
—
SW 1
Closed
—
Closed
Closed
SW IZ
—
—
—
Closed
Reference Figures
* Assumes a positive polarity input signal. SW RI would be closed for a negative input signal.
DS21460D-page 6
? 2007 Microchip Technology Inc.
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相关代理商/技术参数 |
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| TC7135CLI713 | 功能描述:LED显示驱动器 4-1/2 Digit A/D BCD RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
| TC7135CPI | 功能描述:LED显示驱动器 4-1/2 Digit A/D BCD RoHS:否 制造商:Micrel 数位数量:5 片段数量: 安装风格:SMD/SMT 封装 / 箱体:PLCC-44 工作电源电压:4.75 V to 11 V 最大电源电流:10 mA 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Tube |
| TC7135CPL | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:4-1/2 Digit A/D Converter |
| TC7136 | 制造商:MICROCHIP 制造商全称:Microchip Technology 功能描述:Low Power 3-1/2 Digit Analog-to-Digital Converter |
| TC7136A | 制造商:TELCOM 制造商全称:TelCom Semiconductor, Inc 功能描述:LOW POWER, 3-1/2 DIGIT ANALOG-TO-DIGITAL CONVERTERS |
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