To ensure proper driving of Mirrorcle’s gimbal-less MEMS mirrors, several hardware solutions are available tailored to the specific needs of various applications. They ensure finely controllable tip/tilt movement of the MEMS mirrors to large angles. Hardware options range from basic drivers that take low voltage analog signals or digital SPI signals to convert to high voltage MEMS drive signals, to more complex controllers with microcontrollers or FPGAs. Significant efforts have been allocated since inception of this MEMS technology to continually improve and miniaturize driver electronics, resulting in very small, low noise, very low power consuming driver solutions.
The lowest recommended level of integration in applications is to use the MEMS mirror with a designated driver to provide properly conditioned voltage signals. These drivers are the lowest level of electronics integration and require users to supply suitable X and Y position voltages or signals, power, ground and a TTL clock signal for low pass filters.
The driver footprint was recently reduced to 35mm x 40mm x 9mm or about half the size of a credit card. These drivers are optimized to safely drive MEMS mirrors and include programmable 5th order low-pass filters (LPF) for smoothing output voltages, a high voltage DC/DC circuit and a high voltage amplifier. The drivers output two bias-differential pairs (four total channels) that range from 0V to 200V, allowing for Vbias voltages up to 100V. These MEMS drivers require only +5V DC voltage supply and consume approximately 70mW of power, making them especially suitable for battery-powered or portable applications. The bandwidth of the standard drivers is up to 25kHz, however, in actual applications, the bandwidth is determined by the user-set LPFs which should match an individual MEMS mirror’s recommended filter cut-off setting as defined in its datasheet.
Breakout PCBA for Input connector of MEMS Drivers
P/N: BRK-DRIVER-5.x
Breakout PCBA for Input connector of MEMS Drivers
PCBA which breaks out the input connection side of both digital and analog-input MEMS driver to easy to use terminals or test points / pins. Each pin of the 10-pin connector has its own screw terminal connection and easy to read label. Recommended and prepared for first-time users of Mirrorcle’s MEMS Drivers. Typically a new user should purchase one of these PCBAs with the first purchase of a MEMS Driver 5.x.
- INPUT: Screw terminals, test points, connect pins – multiple options for easy connections to the driver inputs.
- OUTPUT: 10-pin header connector (0.05″, 2 rows, right angle) which can be directly connected to MEMS Drivers (Analog and Digital) of 5.x generations.
MEMS Drivers 5.X Features
Low voltage supply and low power consumption (<100mW)
Four high voltage output channels (two biased differential pairs) (~0V up to 200V)
Small form factor, approximately ½ of a credit card size: 35mm x 40mm x 9mm
Power supply monitoring with auto-shutdown
Bandwidth up to 25kHz (governed by the user-set LPFs)
(Optional for larger quantities) Four continuous time low pass filters.
Embedded regulated DC/DC converter creates high voltage supply from the +5VDC supply (VDD)
Four embedded Bessel low pass filters. User-provided clock sets cut-off frequency for all four LPFs with separate control for X and Y axis.
Analog Input – Two analog inputs for X and Y axis drive (+/- 10V)
Digital Input – SPI digital inputs for X and Y axis drive (3VTTL)
Driving the Mirrors – The BDQ Principle
Bias-Differential Quad-channel (BDQ) is the proper methodology for driving Mirrorcle MEMS Mirrors.
- All four channels are biased to 80V (Vbias). This is MEMS mirror origin/rest position.
- Pairs of channels apply (biased) differential voltages from ~0V to 160V. Mirror rotates approximately proportionally to the applied Vdifference for each axis.
- Vdifference (X-axis) = HV_A – HV_B
- Vdifference (Y-axis) = HV_C – HV_D
In the Analog Input PicoAmp, it is inherently implemented by adding a bias to the four output channels and forcing them as differential pairs.
In the Digital Input PicoAmp this methodology should be implemented by the user by adding a bias value to the four output channels and forcing them as differential pairs.
All Mirrorcle control and driving hardware should be operated in this fashion and all Mirrorcle software supports this mode.