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Unformatted text preview: itors is generally in the 10 pF range. The
purpose of these capacitors is to reduce the RF
radiation that is produced by the arching of the
commutators. BIDIRECTION BDC MOTOR DRIVE (H-BRIDGE) CIRCUIT
VSUPPLY R1 Q1 D1 C1 C3 D3 Q3 D4 Q4 Motor IFWD BDC CTRL3
R3 CTRL1 IRVS IBRK CTRL2 D2 C2 R2 The different drive modes for and H-bridge circuit are
shown in Table 1. In Forward mode and Reverse mode
one side of the bridge is held at ground potential and
the other side at VSUPPLY. In Figure 8 the IFWD and IRVS
arrows illustrate the current paths during the Forward
and Reverse modes of operation. In Coast mode, the
ends of the motor winding are left floating and the motor
coasts to a stop. Brake mode is used to rapidly stop the
BDC motor. In Brake mode, the ends of the motor are
grounded. The motor behaves as a generator when it
is rotating. Shorting the leads of the motor acts as a
load of infinite magnitude bringing the motor to a rapid
halt. The IBRK arrow illustrates this. TABLE 1: C4 CTRL4
R4 Q2 There is one very important considerat...
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This note was uploaded on 01/29/2014 for the course AA AA taught by Professor Aa during the Winter '10 term at ENS Cachan.
- Winter '10