Description

The AS8002 focuses on sensing, monitoring, and converting the voltages and currents across an inverter or micro-inverter to a digital value, especially those that are isolated from the microcontroller such as the grid signal in solar inverters. The digital values of the sensed signals will then be used by the microcontroller to perform the regulation.

In case of power converters in solar photovoltaic systems, these are often connected directly to the electricity grid in order to inject the created energy into the mains and act as an electricity supplier. This energy must comply with certain regulations that set the standard in terms of quality and safety which requires of accurate measurements.

The AS8002 is a highly accurate measurement IC that allows monitoring the generated energy with low cost shunt resistors or other sensors for the current and resistor dividers for the voltage. This approach allows avoiding more expensive sensing devices while achieving the required accuracy for DC and AC measurements of current and voltage
as well as stability over the operating temperature range of the inverter. The 12-bit ADC samples the voltage and current
and provides their instantaneous values through an SPI interface.

The AS8002 is preceded by low noise programmable gain amplifiers in order to accommodate different sensors. The ADC has three multiplexed inputs, offering one secondary channel in addition to the main voltage and current.
The on-chip temperature sensor provides the inverter designer the option of temperature compensation for any of the measured parameters or functional blocks provided, over the full operating temperature range of the device.
The on-chip voltage reference is connected to the ADC and to REF.

An external crystal oscillator is not required as a high accuracy internal oscillator clock is available. The independent over current interrupt detects a high current on the grid and allows the processor to open the switches without waiting for the ADC
conversion.

주요 특징

• 12-bit 100 kSPS ADCs for accurate voltage and current measurement
• Programmable gain amplifiers to accomodate for different sensors
• 3 multiplexed inputs for secondary measurements that require high accuracy and fast sampling rates
• On-chip temperature sensor connected to one of the inputs of the multiplexor
• On-chip voltage reference with small temperature coefficient (25ppm/K typ). This reference is available at the pin REF.
• Low power on chip oscillator
• SPI compatible interface
• Internal registers for easy offset and gain compensation
• Interrupt alerts (including under voltage lock-out and over temperature)
• Independent programmable over current interrupt

적용분야

• PV wind energy, power conditioners and UPS (Uninterrupted Power Supply)

Block diagram for AS8002 Voltage / Current Measurement IC for Solar Inverters and Power Converters