SMPS300REh

Description

SMPS300REh is a dedicated Switched Mode Power Supply for Audio Amplifiers able to deliver full rated power for extended periods of time. It is based on the previous SMPS300RE, with improved efficiency and enhanced cooling, suitable for long-term full high power demand amplifiers such as Class A and class AB high-end Power Amplifiers, as well as Class D amplifiers used for special applications. It uses Half Bridge resonant topology, capable of delivering 300W continuous and up to 350W peak power. SMPS300REh has by default differential output voltage, for single output voltage, refer to SMPS300RS. The stock available output voltages are adjustable within approx. 5-10% range and the ordered voltage value is at the middle of the interval. For example the +-30V version can be adjusted from approx. +-28.5V to +-31.5V. In this way, the available voltage versions covers many of the usual  voltage values used in power amplifiers from +-28V to +-60V or even more when custom voltage is chosen. The main feature of this power supply is the use of the cooling plate both for power switches and rectifier diodes, which due to increased efficiency, up to 95% for higher voltage versions, can serve as a heatsink for most applications if is installed in a thermally conductive enclosure. Unlike any other competitor SMPS on the market the SMPS300REh can deliver the specified power continuously, as long as the cooling demands are met. Also, the amount of EMI is much lower than any competitor’s SMPS especially the old, hard-switched type commonly found on the market and could be compared with a high quality linear regulated power supply.

Stock available voltages are: +-30V, +-36V, +-45V, +-55V and +-60V. Any other voltages in range of +-24V to +-85V are possible, though for voltages below +-30V the output current will be limited to 5A per rail. Mains input voltage, by default is 230V although 120V is available. Due to relatively small space available on the PCB board and very demanding characteristics for this given application, the electrolytic capacitors used on SMPS300REh are chosen to offer the best performance under all operating conditions, to be reliable and operate at high temperature and high ripple currents for extended period of time. Most of the capacitors which met these conditions aren’t visually attractive, shiny or made by some famous brand names but are the most suitable for this given application. Replacing them with “better” capacitors is not recommended and the overall performance and reliability  might be worse with those “better” capacitors. For this reason, each voltage version of SMPS300REh might come with different capacitors on the primary side, 180-200V rated capacitors for 100-120V mains and 350-400V rated capacitors for 220-240V mains, and obviously different capacitors on the secondary side, for different output voltage. Auxiliary output voltage is differential, in range of +-15 to +-20V typical value +-18V with max. 500mA current capability. The auxiliary voltage is unregulated, proportional with the main output voltage, a factor of transformer turns ratio. Auxiliary GND is isolated from main output GND allowing the user to chose best implementation for lowest noise and avoiding GND loops.

SMPS300REh overall size including the aluminum base plate is 100x100mm and it weights about less than 400 grams. The aluminum base has 4 threaded M4 mounting holes, placed in each corner in a 92x92mm pattern. The size and weight is greatly reduced, allowing to install the SMPS300REh into a low profile enclosure, with it’s 100x100mm and 35 to 45mm tall depending on the voltage version and capacitors used.