Device description

L99UDL01

14/24

DB3264 Rev 3

2.4.3

Current feedback

The Integrated drivers can provide a 10 bits word representing the current regulation loop

current value. This is done to provide load integrity information in addition to the CNR bit (a

current not reached, CNR, bit is set if the current in the output does not reach the regulated

current level during the entire on-time actuation).

This is a buffered value of the 10 bits up/down counter in the current regulation loop. This

information is retrieved at the falling edge of CSN when accessing the appropriate current

loop register.

The conversion of the 10 bits information found in registers 13h – 18h to a typical value of

current is a simple equation:

2.4.4

PWM frequency adjustment

The current regulation or PWM control PWM frequency can be adjusted to optimize the

motor current regulation. This is accomplished in 2 kHz intervals from 10 kHz to 24 kHz

using three FPWMx bits in register 00H.

2.4.5

External FET Controllers

The external FET controllers are designed to be drivers for MOSFETS configured as half

bridges. These outputs are not intended to be PWMmed and are limited in their switching

speed to aid in reducing EMC issues.

monitor. Both the voltage threshold and reaction delay are programmable. The default

setting is 1V for 1ms.

In the event of a Drain-Source fault the appropriate fault bit will be set as well as a fault bit in

the Global Status Byte. A faulted driver will be switched off and is enabled again only after

clearing fault bit (register 11H).

Since these outputs are not intended to be PWMmed there is no active recirculation option.

The external MOSFET control has off-state diagnostic capability as well.

The external MOSFETs can be driven in timed on/off control or purely on/off control.

2.4.6

External MOSFET Dead Time Control

At the end of every timed actuation all outputs are pulled to ground for the off-time duration

as determined in the control register 02H. This requires that the external H-Bridge controller

has a dead time between when the high side MOSFET is commanded off and when the low

2.4.7

DOUT

The Data OUT pin provides the host processor with a real time fault indication. The Global

Fault bit may be reflected on this pin.

Typical

Current

Regx

0A0h

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