Solar Inverters

The ADSP-CM41xF series of mixed-signal control processors is based on the ARM^® Cortex-M4™ processor core with floating point unit operating at frequencies up to 240 MHz. In addition, some of the series incorporate an ARM^® Cortex-M0™ processor core operating at frequencies up to 100 MHz which enables the integration of dual-core safety redundancy into a single chip. The processors integrate up to 160K Bytes of SRAM memory with ECC, up to 1M Byte of flash memory with ECC, accelerators and peripherals optimized for photo-voltaic (PV) inverter control and motor control, and an analog module consisting of up to two 16-bit SAR-type ADCs, one 14-bit on M0 ADC and one 12-bit DAC. The ADSP-CM41xF family operates from a single voltage supply, generating its own internal voltage supplies using internal voltage regulators and an external pass transistor.

By integrating a rich set of industry-leading system peripherals and memory, the ADSP-CM41xF mixed signal control processors are the platform of choice for next-generation applications that require RISC programmability and leading-edge signal processing in one integrated package. These applications span a wide array of markets in power conversion and include Solar PV inverters, motor/power control, and battery charging/control.

The ADuM4135 is a single-channel gate driver specifically optimized for driving insulated gate bipolar transistors (IGBTs). Analog Devices, Inc., iCoupler^® technology provides isolation between the input signal and the output gate drive.

The ADuM4135 includes a Miller clamp to provide robust IGBT turn-off with a single-rail supply when the gate voltage drops below 2 V. Operation with unipolar or bipolar secondary supplies is possible, with or without the Miller clamp operation.

The Analog Devices chip scale transformers also provide isolated communication of control information between the high voltage and low voltage domains of the chip. Information on the status of the chip can be read back from dedicated outputs. Control of resetting the device after a fault on the secondary is performed on the primary side of the device.

Integrated onto the ADuM4135 is a desaturation detection circuit that provides protection against high voltage shortcircuit IGBT operation. The desaturation protection contains noise reducing features such as a 300 ns masking time after a switching event to mask voltage spikes due to initial turn-on. An internal 500 µA current source allows low device count and the internal blanking switch allows the addition of an external current source if more noise immunity is needed.

The secondary UVLO is set to 11 V with common IGBT threshold levels taken into consideration.

Applications

• MOSFET/IGBT gate drivers
• PV inverters
• Motor drives
• Power supplies

The AD7401A is a second-order, sigma-delta (Σ-Δ) modulator that converts an analog input signal into a high speed, 1-bit data stream with on-chip digital isolation based on the Analog Devices, Inc., iCoupler^® technology. The AD7401A operates from a 5 V power supply and accepts a pseudo-differential input signal of ±250 mV (±320 mV full scale). The analog input is continuously sampled by the analog modulator, eliminating the need for external sample-and-hold circuitry. The input information is contained in the output stream as a density of ones with a data rate of up to 20 MHz. The original information can be reconstructed with an appropriate digital filter. The serial I/O can use a 5 V or a 3.3 V supply (V_DD2).

The serial interface is digitally isolated. High speed CMOS, combined with Analog Devices, Inc., iCoupler^® technology, means the on-chip isolation provides outstanding performance characteristics, superior to alternatives such as optocoupler devices. The device contains an on-chip reference. The AD7401A is offered in a 16-lead SOIC and has an operating temperature range of −40°C to +125°C.

Applications

• AC motor controls
• Shunt current monitoring
• Data acquisition systems
• Analog-to-digital and opto-isolator replacements