Power tools, toys, gadgets gain smallest gate driver & power MOSFETs
These parts are, says TI, designed around the particular needs of driving BLDC motors in applications such as power tools; for example, the use of low voltages and high currents, where managing stalled-motor or short-circuit conditions can be a problem. With high currents, switching edges can also be a source of EMI.
The DRV832x BLDC gate drivers feature a smart gate-drive architecture that eliminates up to 24 components traditionally used to set the gate drive current while enabling designers to adjust FET switching to optimize power loss and electromagnetic compliance. The CSD88584Q5DC and CSD88599Q5DC power blocks place two FETs in a unique stacked-die configuration, which doubles power density and minimizes the FET resistance and parasitic inductances typically found in side-by-side FET configurations.
An 18-V compact BLDC motor reference design demonstrates how the DRV8323 gate driver and CSD88584Q5DC power block can drive 11 W/cm³ in designs such as smaller, lighter-weight power tools, integrated motor modules, drones and more. (www.ti.com/smallmotordesign-pr-eu)
The combined solution delivers 700W of motor power without a heat sink, providing 50% higher current than conventional solutions without increasing the footprint. The 18-V BLDC reference design shows the smart gate driver and power block are driving a peak current of up to 160A for more than 1 second. The combination enables shorter trace lengths and actively prevents unintended FET turn-on, while also providing undervoltage, overcurrent and thermal protection. Unwanted FET turn-on can be caused by induced transient voltages on the gate at the wrong part of the switching cycle – the driver IC actively pulls the low-side FET’s gate down, rather than merely not driving it, when it should be ‘off’.
The CSD88584Q5DC and CSD88599Q5DC power blocks come in TI’s DualCool thermally enhanced package, which enables designers to apply a heat sink to the top of the device to decrease thermal impedance and increase the amount of power dissipated to maintain safe operating temperatures for the board and end application. Having the two FET chips mounted one above the other is thermally advantageous, TI says; the low-side FET sees higher power dissipation, is mounted uppermost in the package and can be provided with a slightly lower thermal resistance path from the top, balancing the combination. This can, TI says, save up to 3 degrees in an application. The power blocks’ switch-node clip-construction helps eliminate parasitic inductance between high- and low-side FETs. The DRV832x gate driver’s passive component integration minimizes board traces.
Designers can freely parallel the power blocks to increase current rating; the controller IC has independent sense-amplifier inputs for three such connections. Current sensing can be shunt-based, or shunt-less.
In addition to the 18-V BLDC motor reference design, engineers can search for other motor reference designs that use the power blocks and gate drivers to help solve their system design challenges. A three-phase smart gate-driver evaluation module (EVM) allows designers to drive a 15-A, three-phase BLDC motor using the DRV8323R gate driver, CSD88599Q5DC power block and MSP430F5529 microcontroller LaunchPad development kit. The EVM is available for $99.00.
The DRV832x BLDC smart gate drivers offer peripheral and interface options for engineers to select the best device for their design: with or without an integrated buck regulator or three integrated current-shunt amplifiers. Each device option is available in a hardware or serial interface and comes in quad flat no-lead (QFN) packaging. The CSD88584/99 power blocks come in DualCool small outline no-lead (SON) packaging, with 40- or 60-V breakdown voltage (BVDSS) choices.
|
Product |
Price U.S. dollars for 1,000-unit quantities |
Package size |
Key features |
|
DRV8320 |
$1.41 |
5-mm-by-5-mm |
Smart gate drive |
|
DRV8320R |
$2.01 |
6-mm-by-6-mm |
Integrated buck regulator |
|
DRV8323 |
$1.60 |
6-mm-by-6-mm |
Integrated current-shunt amplifiers |
|
DRV8323R |
$2.19 |
7-mm-by-7-mm |
Integrated buck regulator and current-shunt amplifiers |
|
CSD88584Q5DC |
$2.24 |
5-mm-by-6-mm |
40-V BVDSS, 0.68-mΩ typical on-resistance |
|
CSD88599Q5DC |
$2.50 |
5-mm-by-6-mm |
60-V BVDSS, 1.7-mΩ typical on-resistance |
TI; https://www.ti.com/smallmotordesign-pr-eu
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