High Voltage VIPer26K from STMicroeletronics for Low Power SMPS

STMicroelectronics has unveiled the VIPer26K last week, a new member of the VIPer Plus family of devices the company released earlier this year. Components from this group are designed to implement low-power, switched-mode AC to DC power supplies up to a maximum power of 15 watts.

This technology is ideal for bridging devices with a high volume of voltage power available with one that needs only a minimal amount at relatively low voltage.

Specifications

The high voltage control capabilities of the VIPer26K eliminate the need for traditional stacked field-effect transistors and associated passive components to reach similar voltage capability, allowing the potential use of smaller external snubber components. 

The VIPer26K also comes with a built-in rain current-limit as well as a senseFET connection for over-temperature protection.

Moreover, the new component features a high-voltage startup circuitry, a built-in error amplifier, and current-mode PWM controller all integrated on-chip.

Because of this, the VIPer26K  can support all common switched-mode power supply topologies, ranging from isolated flyback with secondary-side or primary-side regulation to non-isolated flyback with resistive feedback, buck, and buck-boost converters.

According to STMicroelectronics, the new component’ s MOSFET (metal-oxide–semiconductor field-effect transistor) breakdown voltage would be the highest on the market. 

This, together with a set of integrated features and minimal external circuitry, should allow designers to save on costs related to bill of materials and board space while increasing efficiency in applications such as power supplies for 1-phase and 3-phase smart energy meters, 3-phase industrial systems, and more.

VIPer26K Block diagram. Image courtesy of STMicroelectronics.

Key Features 

The VIPer26K includes an error amplifier and a current-mode PWM controller and can support such switched-mode power supply topologies as:

• Isolated flyback with secondary-side or primary-side regulation

• Non-isolated flyback with resistive feedback

• Buck converters

• Boost converters

As per the technical sheet, the main features of the VIPer26K are:

• 1050 V avalanche-rugged power MOSFET

• allowing ultra-wide VAC input range to be covered

• Embedded HV startup and sense-FET

• Current mode PWM controller

• Drain current limit protection:

• -500 mA (VIPER265K)

• -700 mA (VIPER267K)

• Jittered switching frequency reduces the EMI filter cost: 60 kHz ± 4kHz

• Standby power < 30 mW at 230 VAC

• Embedded E/A with 3.3 V reference

• Safe auto-restart after a fault condition

• Hysteretic thermal shutdown

• Built-in soft-start for improved system reliability

SO16N package outline. Image courtesy of STMicroelectronics.

Applications

Given its features, typical applications for the VIPer26K would be related to power meters. This is because in these devices power is read only infrequently, so there is no need to feed it continuously. The VIPer26K’s three-phase voltage supply capabilities and at 230 VAC input also allow the component to draw less than 30 mW during no-load periods, making it well suited not only for smart meters applications but also for powering LED display drivers or microcontrollers.

Furthermore, STMicroelectronics noted how the fact that the device includes both a MOSFET and a controller will greatly simplify the design of physically little power supplies where power efficiency and reliability are particularly important. As previously mentioned, the main feature of the VIPer26K is its ultra-efficient MOSFET. The component’s breakdown voltage of 1050 volts can, therefore, work as a replacement for two stacked MOSFETs with lower breakdown voltages.

This not only will enable simpler, smaller and more reliable designs but will also allow the device to operate over a wide range of input voltages and reduce in the size of the DRAIN snubber circuit. With a switching frequency internally fixed at 60 kHz, ± 4kHz, greater control of the MOSFET gate during turn on and turn off is possible, thus minimising switching-noise emissions.