Datasheet

 
SLUS318B – APRIL 1999 – REVISED JANUARY 2002
8
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APPLICATION INFORMATION
The UCC3626 is designed to operate with 120° position sensor encoding. In this format, the three position
sensor signals are never simultaneously high or low. Motors whose sensors provide 60° encoding, can be
converted to 120° using the circuit shown in Figure 1.
In order to prevent noise from commanding improper commutation states, some form of low-pass filtering on
HALLA, HALLB, and HALLC is recommended. Passive RC networks generally work well and should be located
as close as possible to the device. Figure 2 illustrates these techniques.
HALLA
HALLB
HALLC
VREF
2N2222A
HALLA
HALLB
VREF
HALLC
1 kΩ
499 Ω
1 kΩ
1 kΩ
499 Ω
1 kΩ
2.2 nF
2.2 nF
2.2 nF
UDG–97182
Figure 1. Converting Hall Code From 60° to 120°
VREF
HALLA
HALLB
HALLC
VREF
HALLA
HALLB
VREF
HALLC
VREF
1 kΩ
499 Ω
499 Ω
1 kΩ
499 Ω
1 kΩ
2.2 nF
2.2 nF
2.2 nF
UDG–97185
Figure 2. Passive Hall Filtering Technique