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# Using ADC/DAC for High voltage control (temperature dependency)

Category: Hardware

Hello,

I want to read a voltage, originally a current proportional to a temperature measured by a transducer (i.e. an electronic device that converts energy from one form to another) ref: AD590 (datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad590.pdf), in a 12/16 bit resolution. The current-to-voltage conversion resistor is chosen so that VT = 1 mV/°C (R=1k). VT will therefore be equal to ~300 mV at ambient temperature (I'm not sure if I'll add gain or not, maybe I'll just use the amplifier in a voltage follower configuration). This voltage must be read by an ADC and interpreted in such a way as to produce a voltage Vctrl, probably with the help of a DAC, between 0 and 4V, which serves as a reference voltage for a DC-HVDC converter (datasheet: https://www.xppower.com/portals/0/pdfs/SF_AG_Series.pdf) which produces the high voltage which is then used to bias an avalanche photodiode (APD).

I have no idea which product I can use to do this so if you have any ideas please share them. Perhaps you have even seen or used something that could be reused for this project. Thanks.

This diagram should be helpful to understand the project:

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• If you only need to measure the temperature channel with the ADC, then might you consider using one of the digital temperature measurement products? There are quite a few that meet the same 0.5C accuracy spec as the AD590, but give an SPI or I2C interface instead of an analog output. For example, MAX31827, MAX31889, MAX31725, ADT7422, ADT7301, DS620, ...

Selection Table for Digital Temperature Sensors | Parametric Search | Analog Devices
www.analog.com/.../11020

We also offer "thermocouple to digital" converters such as MAX31850 and MAX31855. (Thermocouples support a wider range of temperature measurement.)

If you want a multi-channel ADC to measure other system voltages besides the AD590 analog output voltage, we offer a wide selection of precision A/D converters, such as AD7707, AD7709, LTC2470, MAX11613, MAX1286, etc.

Selection Table for Precision A/D Converters | Parametric Search | Analog Devices
www.analog.com/.../10825

For low-cost precision voltage output DAC, there is AD5761, MAX5717, AD5541, etc.

Selection Table for Single-Supply Voltage Output D/A Converters | Parametric Search | Analog Devices
www.analog.com/.../11061

• If you only need to measure the temperature channel with the ADC, then might you consider using one of the digital temperature measurement products? There are quite a few that meet the same 0.5C accuracy spec as the AD590, but give an SPI or I2C interface instead of an analog output. For example, MAX31827, MAX31889, MAX31725, ADT7422, ADT7301, DS620, ...

Selection Table for Digital Temperature Sensors | Parametric Search | Analog Devices
www.analog.com/.../11020

We also offer "thermocouple to digital" converters such as MAX31850 and MAX31855. (Thermocouples support a wider range of temperature measurement.)

If you want a multi-channel ADC to measure other system voltages besides the AD590 analog output voltage, we offer a wide selection of precision A/D converters, such as AD7707, AD7709, LTC2470, MAX11613, MAX1286, etc.

Selection Table for Precision A/D Converters | Parametric Search | Analog Devices
www.analog.com/.../10825

For low-cost precision voltage output DAC, there is AD5761, MAX5717, AD5541, etc.

Selection Table for Single-Supply Voltage Output D/A Converters | Parametric Search | Analog Devices
www.analog.com/.../11061

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