Fairchild’s Smart power Module products provide efficient motor control for energy restricted low-power inverter-driven applications, such as washing machines and air conditioners. The FSBB20CH60 Motion-SPM integrates three high-voltage ICs (HVICs), one low-voltage IC (LVIC), six IGBTs for three-phase inverter and six fast recovery diodes. Fairchild’s Motion-SPM reduces board space by utilizing an ultra-compact 44mm x 26.8mm Mini-DIP package and by incorporating built-in HVICs that provide an optocoupler-less, single supply IGBT gate driving capability. The FSBB20CH60 product offers designers high reliability with integrated under-voltage lock out (UVLO) and short circuit (SC) protection.

PCB Map

Circuit Layout Design

1. To avoid malfunction, the wiring of each input should be as short as possible. (less than 2–3cm)
2. To prevent protection function errors, the ‘R10’ and ‘Csc’ wiring should be as short as possible.
3. All the by-pass capacitors and filter capacitors should be placed very close to SPM.
4. The short-circuit protection time constant R10 • CSC should be set in the range of 1~2µsec.
5. The isolation distance of DC-P, U-phase, V-phase, W-phase, DC-N/GND blocks should be over
2.54mm(100mil) for 300V~500V P-N voltage.
6. Power-GND and signal-GND should be connected with each other through only one 1.5~2mm width pattern.
7. To prevent surge destruction, the wiring between the filter capacitor and the P & Ground pins should be as short as possible. The use of a high frequency non-inductive capacitor of around 0.1~0.22µF between the P & Ground pins is recommended. In addition to reducing local voltage spikes, the placement and quality of this capacitor will have a direct impact on both conducted and radiated EMI.

Wiring of PCB

The Motion-SPM is installed as the switching module in this evaluation board and has direct interface with the CPU using one shunt resistor. The DC-link(P and N) input terminals are connected into the corresponding terminals in Motion-SPM and three-phase (U,V,W) output terminals from SPM are wired into motor input. Since the three HVICs are integrated in the Motion-SPM, 3 parts of bootstrap circuit are needed, which consists of bootstrap capacitor, charge resistor for charging boost capacitor, blocking diode for high voltage isolation. One shunt resistor is used for sensing short current and the related short current circuit is composed of an external shunt resistor and R-C low pass filter. The signal of fault output pin VFO drops from high level to low when a fault, such as UV (Under Voltage) or SC (Short Circuit), happens. A pull-up resistor and filter capacitor are needed to support this action. Six R-C low pass filters are used between input connector from a DSP controller (or other controllers) and gate input signal pins of Motion-SPM.

Bill of Materials

Source: http://www.fairchildsemi.com