Evolution of brushed DC gate drivers
Looking back on the 20 years of fighting in the field of electronic products, we have come a long way. The components being released in 2015 have unparalleled fineness and integration. Processors are faster, LEDs are brighter, memory is denser, everything consumes less power, and integrated circuits (ICs) integrate more components than ever before.
Next, look at a final product, such as a modern drone (Figure 1).
Figure 1: Modern drone
Is there a 1080p60 camera with source balance ring compensation? It is verified.
Is there a speed controlled brushed DC motor with four output kilowatts? It is verified.
What about remote gigahertz digital transceivers? Not a problem.
Although it is not the brushed DC motor control that comes to mind when you think about the advances in electronics, the technology has been developed for many years. The great thing about brushed motors is that their clever internal construction uses a constant external voltage to switch the direction of the current. The original system can even be run with only the battery and power switch, but that missed some useful features.
A few decades ago, to create a fully functional brushed motor drive, system designers had no choice but to use multiple discrete components. This includes a microcontroller, several gate drivers, a number of relays or metal oxide semiconductor field effect transistors (MOSFETs) used to form the H-bridge, a sense resistor, an op amp circuit to amplify the sense voltage, and one An analog-to-digital converter (ADC) that measures the sense voltage, a fuse for fault protection, and a large number of passive components for various purposes. This method will allow the following features:
Shift function: The H-bridge provides a switch to pulse-width modulate (PWM) the voltage applied to the motor, and the duty cycle directly controls the motor speed.
Two-way control: The H-bridge also allows you to bias a motor with any voltage polarity to allow it to rotate in both directions.
Fault protection: The use of fuses is often a last resort solution, while the sense resistors provide a non-destructive way to measure overcurrent.
Current Control: The sense resistor can also be used to regulate current by disabling the H-bridge at any time.
After years of evolution, all of these features (and other features) have been integrated into a single silicon board. This not only enables IC designers to optimize analog circuits more efficiently in a closed system, but it also allows you to do what you can't do in a discrete way in an IC. For example, thousands of digital logic gates provide serial interface, robust breakdown protection, gate driver current control ("IDRIVE"), fault reporting, and low power modes. In addition, the IC method provides a field effect transistor (FET) VDS detection function, a supply voltage monitor, and a local temperature sensor. The end result: a stand-alone chip takes up very little board space, yet provides high reliability and makes life easier for system designers.
This integration has complemented the advances in analog process technology. As early as the 1990s, TI designed an early series of BiCMOS processes that used "the most advanced" 1μm feature size! Since then, our BiCMOS process nodes have undergone numerous updates, and until 2015, the technology provides intensive digital logic, support for a wide range of voltages, and very low RDS(on) FETs per unit area. The above trend continues as more advanced nodes are about to emerge.
Some designers are still using discrete motor circuits in high current applications (previously for cost and design reuse). This year, we solved this space problem with our first full-bridge gate driver DRV8701. It is competitive in terms of cost and offers the leading edge of all modern IC technologies.
For smaller current brushed motors (up to 3.6A peak), we have just released the 8-pin DRV8871 series. The DRV8871 uses breakthrough technology to detect and regulate motor current without the need for a sense resistor! This avoids power loss, heat dissipation, board space and cost issues associated with sense resistors, and no other device in the world is comparable to it.
Our factory provides 4.3",5", 7" ,9" wired and wireless rear view mirror monitors.Really help you see the image behind your vehicle when you are reversing.
4.3/5/7/9/10.1 inch monitor has a pixel resolution of 800 x 480 /1024*600 and displayed is a sharp clear digital image. Monitor has 2 Channel Video Input; V1/V2 optional. PAL&NTSC for choose. Monitor automatically turns on and switch to Rear View Camera when reversing.
7-Inch TFT LCD screen Monitor with Built-in Wireless Receiver-- High resolution image and full color display.
Rear View Mirror Monitor,Rear View Backup Monitors,Dual Backup Camera Monitor,Rear View Backup Monitor
Shenzhen Sunveytech Co.,LTD , https://www.sunveytech.com