STMicroelectronics

The STEVAL-ISA126V1 is a 5 V-2 A application with 3.3 A peak current capability for 1.9 sec, using VIPer28H, a new off-line high voltage converter from STMicroelectronics. In some applications an SMPS, normally supposed to deliver a certain amount of power, from time to time undergoes load peaks that can be even two or more times as much, but only for a time interval which is short if compared to the thermal time constants of the power components. Typical examples of such loads are printers and audio systems. In these cases, it is more cost-effective to thermally design the system for the maximum continuous power and not for the peak power demand, which will be sustained only for a limited time window. Such a design is possible thanks to the EPT function of VIPER28H, which allows the designer to fix the maximum time window during which the converter is able to manage the peak power still maintaining output voltage regulation. If the overload lasts more than this time window, the converter is automatically shut down in auto-restart mode, in order to avoid the damaging of the power components.

The STEVAL-ISA130V1 demonstration board implements a non-isolated buck topology regulator using the VIPer06, which supplies a 12 V output at up to 140 mA with an operating frequency of 30 kHz. The output voltage of this power supply can be easily set by changing the value of one resistor. The circuit can be powered by either 85 V to 265 V AC or 100 V to 375 V DC.

The STEVAL-ISA132V1 evaluation board implements a converter capable of delivering 170 W of continuous power (VIN= 190 VAC to 264 VAC, VOUT= 24 V) and more than 300 W peak power for a limited time. The architecture of the board is based on a single-stage LLC resonant converter without PFC using the new L6699 resonant controller. The L6699 integrates some very innovative functions such as self-adjusting adaptive dead-time, anti-capacitive mode protection and proprietary "safe-start" procedure preventing hard switching at startup. High efficiency at full load (> 92%) and no load (< 0.6 W) is obtained thanks to the STB13N60M2 (600 V, 0.35 W typ., 11 A) MDmesh M2 power MOSFET in the half-bridge, and the STPS20H100CG (VRRM= 100 V, IF(AV) = 2 x 10 A) Schottky diode for secondary rectification.

The STEVAL-ISA133V1 demonstration board implements a 7.5 W double output wide range mains adapter with constant-voltage/constant-current, designed as an innovative AC-DC adapter to supply a complete power line communication system based on the ST7580. The power supply provides a 13 V output voltage to supply the power line modem (PLM) and the analog circuitry, and a post-regulated 3.3 volts to supply digital circuitry and an optional external microcontroller. The STEVAL-ISA133V1 demonstration board uses the new ALTAIR04-900, a quasi-resonant (QR) current-mode controller IC specifically designed for QR ZVS (zero voltage switching at switch turn-on) flyback converters, which combines a high-performance low-voltage PWM controller chip and a typical 16 RDSon, 900 V, avalanche-rugged power MOSFET in the same package. The device is capable of providing constant output voltage regulation using primary-sensing constant voltage loop (CV loop). This eliminates the need for the optocoupler and the secondary voltage reference while maintaining very accurate regulation. Also, using the primary constant current loop, it is possible to set the maximum deliverable output current without using secondary components or current sensor. The board implements several protection features that considerably increase end-product safety and reliability: auxiliary winding disconnection (or brownout) detection, shorted secondary rectifier detection, and transformer saturation protection, all of which are auto-restart mode.

The STEVAL-ISA134V1 demonstration board is a a 12 V - 4 W power supply in isolated flyback topology using the VIPer06, a new off-line high voltage converter by STMicroelectronics. The VIPer06 features an 800 V avalanche rugged power section, PWM operation at 115 kHz with frequency jittering for lower EMI, cycle-by-cycle current limit with adjustable set point, on-board soft-start and safe auto-restart after a fault condition. Protection features available include thermal shutdown with hysteresis, delayed overload protection, and open loop failure protection (the latter available only if auxiliary winding is used). This flyback converter design is suitable for various applications, such as external adapter or as an auxiliary power supply in consumer equipment.

The STEVAL-ISA138V1 solution evaluation board is a 90 W, wide-range mains, power-factor corrected, AC-DC adapter. Its electrical specifications are tailored to a typical hi-end portable computer power adapter. The architecture is based on a two-stage approach: a front-end PFC pre-regulator based on the L6563H TM PFC controller and a downstream LLC resonant half bridge converter using the new L6699 resonant controller. Thanks to the chipset used, the main features of this design are very high overall efficiency, compliance with ENERGY STAR® eligibility criteria (EPA rev. 2.0 EPS), high efficiency even at light load, and compliance with the new ErP Lot 6 Tier2 requirements. No load input power consumption is very low also, well within the international regulation limits. The controller of the LLC stage is the L6699, integrating innovative functions such as self-adjusting adaptive dead-time, anti-capacitive mode protection and proprietary "safe-start" procedure to prevent hard switching at startup.

The STEVAL-ISA140V1 is a 15 W wide range evaluation board based on the Viper37HE. It is designed as an example of an isolated auxiliary power supply. The board and the transformer were designed and optimized in order to have a very compact size evaluation board.

The STEVAL-ISA141V1 evaluation board is based on the STBB3J fixed-frequency, high-efficiency, buck-boost DC-DC converter providing 1.2 to 5.5 V output voltages starting from a 1.8 to 5.5 V input voltage. The device can operate with input voltages higher than, equal to, or lower than the output voltage making the product suitable for cell lithium-ion applications where the output voltage is within the battery voltage range. The MODE pin allows selecting between auto mode and forced PWM mode, taking advantage of either a lower power consumption or the best dynamic performance.

The STEVAL-ISA144V1 product evaluation board provides the design engineer with a fully functional step-down switching regulator with an output current of up to 1.5 A. The L5983 integrates STMicroelectronics’ step-down switching regulator, together with all the external components required for a typical application. The rated voltage of the input capacitor and Schottky diode rectifier’s 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 L5983 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 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-ISA152V1 product evaluation board is a step-down switching power supply based on the L7987 regulator in an HTSSOP16 package. The output voltage can be set starting from 0.8 V. Low drop-out operation, with almost 100% duty cycle, can be achieved. The L7987 is a 61 V, 3 A step-down asynchronous switching regulator with embedded power MOSFET caable of delivering up to 3 A of current, depending on the application conditions. The embedded switch-over feature on the VBIAS pin and the light load management (pulse skipping) are intended to maximize power conversion efficiency across the entire load range. The soft-start, current limit threshold and the switching frequency are adjustable for application optimization. The device includes an internal 250 kHz oscillator that can be externally adjusted up to 1.5 MHz; two L7987 regulators can be synchronized in a 180° out-of-phase configuration for reduced total input RMS current