What is the difference between a high side and low side driver?

Question

I don not fully grasp the difference between the term High side driver and Low side driver. In specific yet, layman's terms, what do these terms mean?

Answer 1

do you mean in driving terms, if so a high sider is a truck with a trailer body that is 15 feet or more high from ground level. the side of the trailer is classed as a solid mass when it is measured, length approx 6.3m (45 feet ) height approx 8 feet plus. low siders are just short sided trailers or bodies attached to chassis

Answer 2

A half-bridge driver will have 2 switches (transistors, MOSFET's, whatever).  In the case of a typical MOSFET half-bridge, the high-side switch will have it's drain connected to the V-plus voltage, and it's source connected to both the output and the drain of the low-side transistor.  The source of the low-side MOSFET will be connected to common.

http://www.irf.com/product-info/datashee...

This driver has both a low and a high-side driver in one package.  The low-side driver output ("LO") is referenced to COM, like the low-side switch.  But the high-side output ("HO") is referenced to Vs, and Vs is isolated from the rest of the chip - in other words, it floats, and in the example of this driver IC, it's able to float safely by as much as +200 volts from the rest of the chip.  This is necessary because when the low-side switch is turned on, the source of the high-side switch is basically connected to COM, but when the low-side switch is off, the source lead of the high-side switch might be as much as nearly +200V.  And this is what it needs to do in order to control the high-side switch correctly.  Get it?  The HO output will always be referenced to the floating ground Vs, but the 2 together are free to go wherever they need to.  

Notice the diode feeding the Vb terminal and cap?  The diode with the cap make a charge pump - whenever the high transistor is off, the cap will be charged thru the diode via the Vcc.  Once the low-side transistor turns off (and the high on), the diode will be reverse-biased, blocking current, and altho the voltage from Vb to Vs will still be equal to Vcc, the voltage from Vs to COM may be +200, and the voltage from Vb to COM may be say +215, if Vcc is 15V and V+ is +200.  

Email me if not clear (after, of course, giving me a "Best Answer" 8^)

Note: In most apps, the 2 MOSFET outputs shown in the "typical connection" schematic are tied together, and then go into either an inductor if a power supply or Class D amp, or into a motor winding.

Answer 3

if its for road you have to regain speed and release from going down so u wont be so fast . by the way whats poppin beauty

Answer 4

It refers to how you drive a load. High side means your switch is between the plus power and the load; low side means the switch is between the load and negative power.

Say you have a lamp driven by a 12V battery. You attach one end of the lamp to the +12V and one to the negative terminal to make it go. To turn it off, you need to add a switch to the circuit.

For a high side driver, the transistor (switch) is between the +12 and the lamp. So, when the driver is off, the lamp is at ground potential, with little or no current flow. PNP or P channel MOS transistors are used for high side switches. I like high side drivers, but they are harder to do, requiring more components when the logic level and drive voltage don't match, and P type transistors have about 3x more resistance than similar N type.

For a low side driver, the transistor (switch) is between the lamp and ground or the negative line. This is considered less safe, because the lamp has +12V on it even when turned off. NPN or N channel MOS are used for low side switches.