VPOL5A-12-SIP, VPOL5A-12-SMT, VPOL5A-5-SIP

A block diagram of the VPOL5A-12-SIP Series converter is shown in Figure 1. Extremely high efficiency power conversion is achieved through the use of synchronous rectification and drive techniques.

Essentially, the powerful VPOL5A-12-SIP series topology is based on a non-isolated synchronous buck converter. The control loop is optimized for unconditional stability, fast transient response and a very tight line and load regulation. In a typical pre-bias application the VPOL5A-12- SIP series converters do not draw any reverse current at start-up. The output voltage can be adjusted from 0.75 to 5.0vdc, using the TRIM pin with a external resistor. The converter can be shut down via a remote ON/OFF input that is referenced to ground. This input is compatible with popular logic devices; a 'positive' logic input is supplied as standard. Positive logic implies that the converter is enabled if the remote ON/OFF input is high (or floating), and disabled if it is low. The converter is also protected against over-temperature conditions.

Electrical Description
A block diagram of the VPOL5A-12-SMT series converter is shown in Figure 1. Extremely high efficiency power conversion is achieved through the use of synchronous rectification and drive techniques. Essentially, the powerful VPOL5A-12-SMT series topology is based on a non-isolated synchronous buck converter. The control loop is optimized for unconditional stability, fast transient response and a very tight line and load regulation. In a typical pre-bias application the VPOL5A-12-SMT series converters do not draw any reverse current at start-up. The output voltage can be adjusted from 0.75 to 5.0vdc, using the TRIM pin with a external resistor. The converter can be shut down via a remote ON/OFF input that is referenced to ground. This input is compatible with popular logic devices; a 'positive' logic input is supplied as standard. Positive logic implies that the converter is enabled if the remote ON/OFF input is high (or floating), and disabled if it is low. The converter is also protected against over-temperature conditions.

Thermal Packaging and Physical Design.
The VPOL5A-12-SMT series uses a multi-layer FR4 PCB construction. All surface mount power components are placed on one side of the PCB, and all low-power control components are placed on the other side. Thus, the heat dissipation of the power components is optimized, ensuring that control components are not thermally stressed. The converter is an open-frame product and has no case or case pin. The open-frame design has several advantages over encapsulated closed devices. Among these advantages are:

Efficient Thermal Management: the heat is removed from the heat generating components without heating more sensitive, small signal control components.

Environmental: Lead free open-frame converters are more easily re-cycled.

Cost Efficient: No encapsulation. Cost efficient open-frame construction.

Reliable: Efficient cooling provided by open frame construction offers high reliability and easy diagnostics.

This application note describes the features and functions of V-Infinity's VPOL5A-5-SIP series of non-isolated dc-dc converters. These are highly efficient, reliable and compact, high power density, single output dc-dc converters. These "point of load" modules serve the needs specifically of the fixed and mobile telecommunications and computing market, employing economical distributed power architectures. The VPOL5A-5-SIP series provide precisely regulated output voltage range from 0.75 V to 3.63 Vdc over a wide range of input voltage (Vi=3.0 5.5 Vdc) and can operate over an ambient temperature range of 40 to +85 . Ultra-high efficiency operation is achieved through the use of synchronous rectification and drive control techniques.

The modules are fully protected against short circuit and overtemperature conditions. V-Infinity's world class automated manufacturing methods, together with an extensive testing and qualification program, ensure that all VPOL5A-5-SIP series converters are extremely reliable.