Why Power Gems designed a high-power LED power supply
Power Gems specialises in the design and manufacture of high power electronic power supplies primarily for the location lighting market. We have watched with interest the growth of LED lighting fixtures within the entertainment market and seen them develop from relatively puny sources into the substantial fixtures we see today, producing considerable quantities of light.
The power levels of LED have risen to the point where it crosses over with our area of expertise, which is power supplies over 500W and up to 24kW. The time is right for us to introduce our new range of high power LED supplies, optimised for the cinema market, and as you’d expect from Power Gems fully-featured.
LED lighting power supply
Most LED fixtures are driven using a low-cost, off-the-shelf power supply coupled to a chopping stage to achieve dimming. It’s a straightforward solution, although it does have drawbacks as we discuss later, and requires electronic engineering input from the fixture manufacturer.
For the last 25 years, Power Gems co-owner and product designer, Phil Ellams has specialised in ballasts for HMI lighting, which makes him a whizz at design, prototype and production.
“The idea is not to displace these simple solutions which work well for many applications,” says Phil. “We’re coming at this with our knowledge of very high power fixtures in the HMI market, and we’re producing a premium product for flawless light output in very high power fixtures – particularly for hard-edged luminaires using compact COB (chip on board) sources which are starting to come to market.”
Light, compact, reliable
Chopping or PWM-ing LEDs provides an ‘ok’ answer, but the premium solution, Phil believes, is to drive LEDs with a constant current. However, this entails a more complex power supply.
Additionally, for high power fixtures, it makes sense to allow the power supply to drive higher voltage LED strings than is typical at the moment.
In the case of large light panels, it makes sense to stick with a 48V maximum so it complies with Safety Extra Low Voltage (SELV) levels and little protection is required for the user.
However low voltage means higher current as the power goes up; you can end up requiring heavy PCB tracking or cabling and experiencing undesirable volt drop.
These issues increase with power, and particularly for a compact COB source, it becomes desirable to raise the operating voltage.
Our new range of supplies will operate LED strings up to 150V, and we aim to go higher in the future.
Really flicker-free?
In our opinion only the best will do. Says Phil “As a long-standing manufacturer of flicker-free lighting power supplies we need to be certain that our LED supplies meet the same high standards, and that means using a constant current solution to guarantee flicker-free performance.”
Chopping the output is the simplest option, but introduces flicker, and certain cameras at certain speeds are likely to see that flicker. In developing our range of power supplies for LED lighting, we have used constant current, which is more complicated, but it is absolutely flicker-free under all conditions.
By improving the design, we’ve solved the flicker problem and come up with a high-power high-quality cinema-ready solution.”
Camera-ready
The two Power Gems products are a 600W/900W and a 1200W/1800W power supply.
Features:
- Power supply and driver integrated into one unit.
- 6 continuous current output drivers.
- Flicker-free at all dimming levels.
- Optically isolated serial input and output interface (can support DMX, SPI etc).
Basically, you don’t have to worry about anything in the fixtures apart from the LEDs. Everything else is covered by Power Gems in a single unit – it’s a power supply and driver, giving you 6 channel output.
Phil designs at the Manchester HQ, and it’s here that all ballasts are made. If you need an LED power supply custom-made, we’re equipped to design for your application – event lighting, solar simulation, high speed photography or film and TV lighting. To find out more get in touch
