STMicroelectronics

The STEVAL-ISA154V1 product evaluation board provides the design engineer with a fully functional step-down switching regulator with an output current of up to 0.7 A. The STEVAL-ISA154V1 integrates STMicroelectronics' L5980 step-down switching regulator together with all the external components required for a typical application. The rated voltage of the input capacitor and the Schottky diode rectifier repetitive peak reverse voltage are both 25 V, making the board capable of covering the entire 2.9 V - 18 V input voltage range of the L5980 device. The board features an external resistor divider (R1 and R2) designed for an output voltage of 3.3 V. The output voltage can be set to a level from 0.6 V up to the rated voltage of the output capacitor (16 V). The compensation network on the evaluation board allows the use of an MLCC as output filter to keep the loop stable. The inductor saturation current and forward current of the Schottky diode are within the current limit values. The switching frequency on the board is set to 500 kHz by means of the R5 resistor connected to pin Fsw.

The STEVAL-ISA158V1 is a product evaluation board based on ST's A6986, a 38 V, 2 A synchronous step-down switching regulator with 30 µA of quiescent current. It is designed for automotive system battery-powered applications. It can be used in low consumption mode (LCM) such as in car body implementations, or in low noise mode (LNM) such as in car audio applications.

The STEVAL-ISA159V1 product evaluation board is based on L6984, a high-efficiency monolithic synchronous step-down regulator, capable of delivering up to 400 mA of DC current. The fixed 3.3 V output requires no external resistor divider. The L6984 is suited for home appliances, factory and building automation. The Low Consumption Mode (LCM) is designed for eco-friendly home appliances and automotive applications active during car parking, so it maximizes the efficiency at light load with controlled output voltage ripple. The Low Noise Mode (LNM) makes the switching frequency nearly constant over the load current range, serving low noise application specifications such as audio and sensors. The PGOOD open collector output can implement output voltage sequencing during the power-up phase. The synchronous rectification, designed for high efficiency at medium-heavy load, and the high switching frequency capability ensure a compact application size. Pulse-by-pulse current sensing on the low-side power element implements effective constant current protection.

The STEVAL-ISA160V1 evaluation board is based on the AST1S31HF internally compensated 2.3 MHz fixed-frequency PWM synchronous step-down regulator. The device operates on a 2.8 V to 4.0 V input voltage and provides a regulated output voltage from as low as 0.8 V up to Vin. The peak current mode control with internal compensation delivers a very compact solution with a minimum component count. All the components on the evaluation board are automotive grade.

The STEVAL-ISA172V2 is a 2 kW fully digital switch mode AC-DC converter consisting of two power sections: a two phase interleaved power factor corrector (PFC) and a DC-DC phase-shifted full-bridge converter, controlled by a STM32F334 microcontroller for each section. The interleaved PFC comprises two boost converters operating with 180° out of phase, based on 600 V MDmesh M2 Power MOSFETs. The downstream section comprises of a DC-DC phase-shifted full-bridge converter based on MDmesh DM2 Power MOSFETs and performing voltage step down using HF transformer, with a primary to secondary ratio chosen to maintain high enough efficiency and regulation over the entire operating range. On the primary side the transformer is supplied by the full-bridge converter and switching losses are reduced thanks to zero voltage switching (ZVS) operation. On the secondary side synchronous rectification (SR) is used to ensure low conduction losses. The output voltage waveform is rectified by STripFET Power MOSFETs and then smoothed by the output filter.

The key feature of this offline converter is Zero-Power Mode (ZPM). It is an idle state during which the device is totally shut down and the residual consumption from the mains at 230 VACis kept below 10 mW. The IC enters ZPM by pulling the OFF pin to SGND for more than 10 ms and exits ZPM (resuming normal switching) by pulling the ON pin to SGND for more than 20 µs. This function can be tested by acting on the tactile switches connected to the ON and OFF pins. The negative voltage setup is extremely simplified thanks to an embedded error amplifier, whose accurate 1.2 V internal reference (FB pin) is referred to a separate ground (EAGND pin) that can drift down to -12.5 V with respect to the signal ground of the IC (SGND). The negative output (OUT1) is obtained by just connecting EAGND to the negative rail and a voltage divider between FB, EAGND and SGND. The positive output (OUT2) is obtained from OUT1 through the turn ratio of the secondary windings of the transformer. To achieve extremely low input power consumption, the IC is biased through a diode coming from the OUT2, which maintains the VCCvoltage high enough (> 4.5 V) to prevent the activation of the internal HV current source.

STEVAL-ISA178V1 is a compact and efficient solution for AC-DC power supplies, and performs voltage conversion from the main line down to 5 V output voltage. The low current consumption of the VIPer01 and its low VCC voltage allows extremely low input power consumption under no load and light load conditions. The pulse skip feature embedded in our IC reduces the peak current typically present during the startup phase of a buck converter.

The STEVAL-ISA182V1 evaluation board implements an isolated flyback converter (12 V / 0.7 A) 8.4 W (30 W peak), US range 85 – 132 VAC, developed for metering. The core of the application is the VIPER38HD, the latest offline converter from the VIPerPlus family. The device is a high-voltage converter that intelligently integrates an 800 V rugged power MOSFET with PWM current-mode control. The device features an adjustable extra power timer (EPT) that enables the IC to sustain overload conditions for a few seconds. The main characteristics of the evaluation board are its small size, minimal BoM, high efficiency and low standby consumption. Extremely low consumption under the no-load condition is ensured thanks to burst mode operation that reduces the average switching frequency and minimizes all frequency related losses. VIPER38HD operates at 115 kHz fixed frequency. Frequency jittering is implemented to help meet the standards regarding electromagnetic disturbance. The IC features high-level protections like dual-level OCP, output overvoltage, short-circuits and thermal shutdown with hysteresis. After the removal of a fault condition, the IC is automatically restarted.

The STEVAL-ISA184V1 evaluation board implements an isolated flyback double output (5 V / 1.2 A and 12 V / 0.75 A) 15 W wide range mains developed for general purpose applications. The core of the application is the VIPer37LD off-line high voltage converter from the VIPerPlus family. The device is a high-voltage converter that intelligently integrates an 800 V rugged power MOSFET with PWM current-mode control. The main characteristics of the evaluation board are its small size and minimal BOM, high efficiency and low standby consumption. Extremely low consumption under no-load conditions is ensured thanks to burst mode operation, which reduces the average switching frequency and minimizes all frequency-related losses. The VIPer37LD operates at 60 kHz fixed frequency, and frequency jittering is implemented to help meet the standards regarding electromagnetic disturbance. The several protections on the device like overvoltage, overload, output short circuit, secondary winding short, hard transformer saturation protection and brown out protections improve the safety and reliability of the design.

The STEVAL-ISA189V1 is a product evaluation board based on the ST synchronous step-down switching regulator A6986F5V, which can deliver up to 1.5 A and, with its 100% duty cycle ability to withstand cold crank events and wide input operating voltage range, represents the ideal choice for battery-powered automotive systems. Synchronous rectification helps achieve higher efficiency at full load as well as application compactness, while high-frequency switching (programmable up to 2 MHz) helps reduce the cost and size of power passive components while remaining outside the AM band. The device can operate in low consumption mode (LCM), with a quiescent current of 30 μA that ensures high efficiency under light load, which is a requirement in typical car body applications that are active when a car is parked. A low noise mode (LNM) can be selected to meet the requirements of infotainment applications with forced PWM mode under all load conditions. The default board configuration is LCM active, 500 kHz switching frequency, high ISKIPcurrent and the switchover feature enabled, but all of these settings can be easily changed so the user can evaluate different application scenarios.