SLVSEC9C September 2019 – February 2020 DRV8904-Q1 , DRV8906-Q1 , DRV8908-Q1 , DRV8910-Q1 , DRV8912-Q1
PRODUCTION DATA.
Parallel mode in DRV89XX-Q1 device is implemented to support higher current loads which cannot be supported by a single channel. This mode can also be used for reducing the effective on-state resistance (RDS(ON)) for achieving a better thermal performance of the device.
The configuration of various mode is very similar to the single half-bridge operation as explained in Continuous Mode (Without PWM) section. Considering six half-bridges for the parallel operation (OUT1, OUT2, OUT3 as group -
'X' and OUT4, OUT5, OUT6 as group 'Y'), various modes can be summarized in Table 5.
nSLEEP | HALF-BRIDGE-1
HALF-BRIDGE-2 HALF-BRIDGE-3 (X) |
HALF-BRIDGE-4
HALF-BRIDGE-5 HALF-BRIDGE-6 (Y) |
OUT1
OUT2 OUT3 |
OUT4
OUT5 OUT6 |
BRIDGE OPERATION
(DC MOTOR) |
---|---|---|---|---|---|
0 | HBX_HS_EN = Don't Care
HBX_LS_EN = Don't Care |
HBY_HS_EN = Don't Care
HBY_LS_EN = Don't Care |
Z | Z | Sleep Mode |
1 | HBX_HS_EN = 0
HBX_LS_EN = 0 |
HBY_HS_EN = 0
HBY_LS_EN = 0 |
Z | Z | Motor Coast |
1 | HBX_HS_EN = 1
HBX_LS_EN = 0 |
HBY_HS_EN = 0
HBY_LS_EN = 1 |
H | L | Forward Direction |
1 | HBX_HS_EN = 0
HBX_LS_EN = 1 |
HBY_HS_EN = 1
HBY_LS_EN = 0 |
L | H | Reverse Direction |
1 | HBX_HS_EN = 0
HBX_LS_EN =1 |
HBY_HS_EN = 0
HBY_LS_EN = 1 |
L | L | Motor Brake (Low-Side) |
1 | HBX_HS_EN =1
HBX_LS_EN = 0 |
HBY_HS_EN = 1
HBY_LS_EN = 0 |
H | H | Motor Brake (High-Side) |
1 | HBX_HS_EN = 1
HBX_LS_EN = 1 |
HBY_HS_EN = 1
HBY_LS_EN = 1 |
Z | Z | Motor Coast |
NOTE
For parallel mode operation, the device operation under safe operating area (SOA) is recommended for supply voltage, VVM ≤ 20-V, HBX_SR = HBY_SR = 1b, tOCP ≤ 10-µs and PL_MODE_EN = 01b.
Figure 38 shows three half-bridges (OUT1, OUT2 and OUT3) operating as a parallel high-side switch and other three half-bridges (OUT4, OUT5 and OUT6) are operating as a parallel low-side switch for achieving a forward motor operation. Similarly the reverse direction of motor is achieved by operation of OUT1, OUT2 and OUT3 as a parallel low-side switch and other three half-bridges (OUT4, OUT5 and OUT6) as parallel high-side switch as shown in Figure 39.
Figure 40 and Figure 41 shows the bridge operation in coast mode with motor initially running in forward and reverse direction respectively. As shown in these figures, the body diodes of the FETs conducts to continue the current flow path due to energy stored in motor's inductance.
The low-side braking of the motor during all the low-side FET's of the driver turning ON is shown in Figure 42. In this case, the motor is considered to be operating in forward direction (current flow from OUT1/2/3 to OUT4/5/6) and then braking is applied. similarly, for the high-side braking, all high-side FET's of the driver are turned ON as shown in Figure 43.