Datasheet LTC4151 (Analog Devices) - 8

ManufacturerAnalog Devices
DescriptionHigh Voltage I2C Current and Voltage Monitor
Pages / Page18 / 8 — applicaTions inForMaTion. Data Converter. Figure 1. Monitoring High Side …
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applicaTions inForMaTion. Data Converter. Figure 1. Monitoring High Side Current and Voltages Using the LTC4151

applicaTions inForMaTion Data Converter Figure 1 Monitoring High Side Current and Voltages Using the LTC4151

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LTC4151
applicaTions inForMaTion
The LTC4151 offers a compact complete solution for high code of each measured voltage is stored in two adjacent side power monitoring. With a wide operating voltage registers out of the six total data registers A through F, range from 7V to 80V, this device is ideal for a variety of with the eight MSBs in the first register and the four LSBs applications including consumer, automotive, industrial in the second (Table 2). and telecom infrastructure. The simple application circuit as The data in registers A through F is refreshed at a frequency shown in Figure 1 provides monitoring of high side current of 7.5Hz in continuous scan mode. Setting control register with a 0.02W resistor (4.096A in full scale), input voltage bit G4 (Table 6) invokes a test mode that halts updating (102.4V in full scale) and an external voltage (2.048V in of these registers so that they can be written to and read full scale), all with an internal 12-bit resolution ADC. from for software testing.
Data Converter
The data converter features a snapshot mode allowing us- ers to make one-time measurements of a selected voltage The LTC4151 features an onboard, 12-bit ∆Σ A/D (either the SENSE voltage, V converter (ADC) that continuously monitors three volt- IN voltage, or ADIN voltage). To enable snapshot mode, set control register bit G7 and ages in the sequence of (VSENSE+ – VSENSE–) first, VIN write the 2-bit code of the desired ADC channel to G6 second and VADIN third. The ∆Σ architecture inherently and G5 (Table 6) using a Write Byte command. When the averages signal noise during the measurement period. Write Byte command is completed, the ADC measures the The differential voltage between SENSE+ and SENSE– is selected voltage and a Busy Bit in the LSB data register is monitored with an 81.92mV full scale and 20µV resolu- set to indicate that the data is not ready. After complet- tion that allows accurate measurement of the high side ing the conversion, the ADC is halted and the Busy Bit is input current. SENSE+ is a Kelvin sense pin for the VIN reset to indicate that the data is ready. To make another pin and must be connected to VIN (see Figure 10) for measurement of the same voltage or to measure another proper ADC readout. The supply voltage at VIN is directly voltage, first disable the snapshot mode for the previous measured with a 102.4V full scale and 25mV resolution. measurement by clearing control bit G7, then re-enable the The voltage at the uncommitted ADIN pin is measured snapshot mode and write the code of the desired voltage with a 2.048V full scale and 0.5mV resolution that allows according to the procedure described above. The Busy Bit monitoring of any external voltage. The 12-bit digital remains reset in the continuous scan mode. 0.02Ω V 3.3V IN V 7V TO 80V OUT SENSE+ SENSE– VDD 2k 2k LTC4151 VIN µ-CONTROLLER SHDN SCL SCL SDA ADR1 SDA GND 4151 F01 ADR0 ADIN VADIN GND
Figure 1. Monitoring High Side Current and Voltages Using the LTC4151
4151ff 8 For more information www.linear.com/LTC4151 Document Outline Features Applications Description Typical Application Absolute Maximum Ratings Pin Configuration Order Information Electrical Characteristics Typical Performance Characteristics Pin Functions Block Diagram Operation Applications Information Typical Application Package Description Revision History Typical Application Related Parts