3 Application Considerations

In appliance applications such as cordless power tools or other home appliances that include a motor drive, important design considerations can include cost, total design size, and ease of use. Device specification considerations can include maximum bootstrap supply voltage, negative voltage transient handling, gate driver VDD supply voltage, undervoltage lockout, and drive current. See Table 4-1 to compare TI gate drivers with single input capability, enable or shutdown pins, fixed or adjustable deadtime, interlock, and integrated bootstrap diode features. Figure 3-1 shows where gate drivers can be used to control multiple BLDC, Permanent Magnet Synchronous Motor (PMSM), or brushed DC (BDC) motors in an application such as cordless vacuum cleaners.

A 100V half-bridge driver such as LM5106 or LM2105 is designed for a small appliance motor drive application. LM5106 has a high absolute maximum bootstrap supply voltage of 118V which supports a 100 % switching voltage transient margin in a 12V VDD system with 12V to 48V motor drive supply. The 1.2A of source current and 1.8A of sink current is designed for DC motor drive switching frequencies and LM5106 also features a single PWM input, enable input, and adjustable dead time in a compact 4x4 mm WSON or 3 × 3mm VSSOP package.

If total design size is a major concern, LM2105 is available in a small 2 × 2mm WSON package with an integrated bootstrap diode. If a leaded package is required, the 5× 4mm SOIC package is available and the lack of need for an external bootstrap diode and resistor reduces the overall footprint. LM2105 also provides sufficient maximum HS pin voltage margin for a typical 12V to 48V motor drive system and high -19.5V negative voltage handling for large negative transients.

To read more on motor drive applications, see How to Choose a Gate Driver for DC Motor Drives.