LCDs for battery powered products
Many of the older 5V LCD technology has been replaced with equivalent 3V LCD modules. As our society becomes more and more mobile, the need for portable, battery powered electronic products increases. Hence the need for low power LCD modules.
The majority of character displays that Focus Display Solutions holds in inventory can be supplied as a 3.3 volt version (VOP = Operating voltage). In fact, most character, graphic and segment displays can operate at 3.3V as long as the glass size is small enough.
Why 3V LCD modules
Many battery powered products are driven off of two ‘AA’ batteries. As a general rule, one ‘AA’ battery can generate between 1.5V and 1.65V.
So, two AA batteries can provide between 3V to 3.3 volts.
In any battery powered product that uses a LCD, we recommend adding a voltage regulator to keep a constant power draw. If the power to the LCD drops too low, the contrast will suffer.
Note: it is not the voltage that drains the battery, but the current draw. One AA battery will last an hour when driven at 1.5V for 2.8 Amps. So the less power you need; the better.
How low of a voltage can the LCD operate on?
As a general rule, we do not recommend dropping below 2.7 Volts when driving the display. At this point two things happen:
- The contrast becomes poor
- The display will cease to operate as the ambient temperature drops
Low power LCDs with a LED backlight
One key method to extending the life of the batteries is to avoid or greatly limit the use of a LED backlight. In some cases, the backlight will draw 50% to 90% more power (current) than the LCD. LED backlight draw around 15mAs.
If you must have a backlight, have it turn off as soon as possible or add a current limiting resistor to dim the backlight.
Custom low power LCDs
Focus Display Solutions has over fifteen years’ experience in supplying custom LCDs. If you have a need for a non-standard display to operate at low power, contact one of our US based technical staff at 480-503-4295. We pride ourselves on same day solutions.
We are receiving more and more requests for 3V LCD modules. One of the main reasons for this is the move from 120V power to battery power. One of the most common size batteries in use is the AA battery. The standard AA battery can supply between 1.25V to 1.65V per battery. When two batteries are used the voltage meets the 3V minimum.
Below is a chart of typical voltage/current ratings on AA batteries.
|Typical capacity||1100 mAh||2700–2900 mAh||3000 mAh||500–1100 mAh||1500–3000 mAh||1500 mAh|
Monochrome LCDs, Custom LCD displays and Graphic LCD displays have the ability to operate at 3V. These displays can also be supplied with LED backlights that will operate at 3V.
* If you have a need for an EL backlight, you need to be aware that this will require an inverter.
Character Displays including all options below are available in 3V.
8×1 LCD displays, 8×2 LCD displays, 16×1 LCD displays, 16×2 LCD displays, 16×4 LCD displays, 20×2 LCD displays, 20×4 LCD displays, 24×2 LCD displays, 40×1 LCD displays, 40×2 LCD displays, 40×4 LCD displays
Static Displays including STN displays and FSTN displays, will operate at 3V. Below are the most common options of segment displays.
Seven segment LCD display (7 segment), 4 digit LCD display, Fourteen segment LCD display (14 segment), Sixteen segment LCD display (16 segment).