Smart Microsystems

The LFHB Sine Wave Home UPS design is a low cost Inverter system design using DSP enabled micro controller with built in MAC and analog capability to deliver excellent performance. The system is programmable at OEM locations, easily field serviceable, and enjoys protection against many power related conditions such as short circuit, overload, battery low, battery fail, high mains voltage, as well as possible field conditions occurring such as feedback failure, temperature faults and others.
The controllers are available with us always, for purchase from us, online or offline.
The system is also computer compatible.
Further modification in future versions may change any and/or all of these circuits to improve performance and/or any other purposes at our discretion. We hold the right to do so for all time.


The features enjoyed by the our Digital Solar Home UPS design are:

  1. Very low cost BOM - less than Rs 3500.00 including everything for 1KVA 12volts at retail prices for components(in quantities of 1). In higher quantities, the prices should drop by at least 25% or more. The change-able components for the different capacity systems are only the transformer, the power supply and MOSFETS.
  2. All PTH components (meaning no SMD components used) to enable easy servicing at remote locations and to reduce service calls.

  3. Computer compatibility for one computer along with other lighting loads.

  4. CC-CV Controlled charging with high Power Factor loading on mains. The charging continues till 128VAC (tested and verified).

  5. Factory preset battery charging voltage limits, and the charging current limits can also be set by the design engineer, depending on technology transfer type.

  6. Design preset overload and surge load (short circuit) limits, which can be changed depending on technology transfer type.

  7. LED as well as LCD can be used together, if required.

  8. Temperature controlled fan circuit that extends life of fan.

  9. Temperature tracking by CPU to ensure fault free operation.

  10. Single sided PCB with everything built in, except the CPU board and two other tiny single sided boards.

  11. Error display on LCD as well as on LED on fault occurrence.

  12. Overload restart three times, design settable. Full stop of operations takes place after three restarts complete, till service personnel reset the counter.

  13. MOSFET and system short circuit protection is instantaneous, and within the CPU to ensure no further external discrete components to depend on.

  14. Pure Sine wave output.

  15. Watchdog Timer implemented to ensure continuous working.

  16. Less than 40dB sound level at 1 meter distance

  17. Discrete device based MOSFET drive to reduce cost and to ensure easy serviceability even in remote areas.

  18. Full H bridge based design that is usable up to high power levels

  19. The single board has been tested up to 24 volts, is capable of going to 48 volts. The system capacities tested till now are 1KVA on 12V and 1.5KVA on 24 volts.

  20. Limited usage of complex/hard to get ICs to ensure easy servicing

  21. Mains sensing without extra transformer.

  22. Multi toned beeper to allow signature switch ON tones for OEMs and for ease in testing and servicing

  23. Uses DSP enabled microcontroller with built in MAC and Analog blocks to eliminate various external circuitry.

  24. Extensive documentation ensures easy and quick time to market for OEMs.

  25. Feedback failure protection for both Inverter as well as charging.

  26. There is a simple single jumper and link arrangement to enable solar charging, along with the solar charger card and connector.

  27. Easy programming setting to choose between 12V, 24, and higher battery configurations and capacities, that can be set by the OEM or service technician with the authorized password.

  28. Very easy to service.

  29. Completely modular design

  30. You get the backing and support of our 22 year old company, with happy customers since 21 years.

  31. You get the experience of a technical team with 37 years total experience. We are here to stay.

Please note that this is NOT a PIC microcontroller based system.


There are different ways we can perform a technology transfer with you. You can decide between:
Type ​1. ​Assembled ​​and tested Cards - Rs.25,000.00
We send you the assembled and tested cards with CPU installed​, and you ​mount, wire the same ​in your own cabinet, with our CPU. ​Then you final test/run and install the system at the customer premises. ​ The transformer winding details, and the schematic of the system will be given as deliverables.
Type 2. Without source code or CPU board - Please contact us here
Type 3. With Source code included - Please contact us here

Training: Depending on the type of technology transfer, we will provide board test, assembly, source code detailed explanation, and testing and installation training to (up to) 4 capable and technically sound people of your team at Mysore. The training period varies depending on type of Technology transfer, from one day for type 1 to 15 days for type 3. You will pay the expenditure involved in boarding, lodging and other expenses for the people of your team. The same members who have been trained will be the people we will interact with for all future support calls during the year.

Support: We give one year support by email and phone. All your technical issues regarding the product can be discussed with us for this period.
All firmware upgrades for one year are also included in the support.