ZIOL2201 datasheet(25/92 Pages) RENESAS

25 / 92 page

ZIOL2xxx Datasheet

April 26, 2016

3.3.5.

IC Self-Protection – Lock Mode

In order to prevent serious IC damage due to overloaded or overheated driver transistors, the IC has a build-in

protection mechanism. If a critical situation occurs for a certain configurable time, the IC can protect itself in

transferring its control in a special mode, called lock mode, in which the driver of the related channel is turned-off

in case of over-current, or in case of over-temperature the drivers of both channels are turned-off, respectively.

Figure 3.8 shows the basic scheme of the IC self protection. In principle, this scheme is five times implemented in

order to tread:

• Over-current situations separately at the high side and at the low side switch of the COM channel as

described in Figure 3.15

• Over-current situations separately at the high side and at the low side switch of the AUX channel as

described in Figure 3.16

• Over-temperature situations of the silicon die as described in Figure 3.17

In case of an over-current or over-temperature situation occurs (in the following called overload) the related over-

current/over-temperature counter (overload counter) will count up. Since the overload counter counts down to

zero in case of no overload is existent, the circuit performs an integrator function. This integrator function makes

sure that overloads which temporarily occur are not accumulated thus will not lead to an unwanted driver locks.

If the overload counter has reached the (in the related configuration register) defined maximum value, the IC will

generate an internal exception. This exception will lock the associated channel or both channels in case of an

over-temperature situation. The “assert Time” (refer to Figure 3.8) which is the elapsed time in until reaching the

configured maximum of the overload counter depends on the used clock period for the overload counter. This

clock period can be defined separately for the lock control circuit of each channel (Figure 3.15, Figure 3.16) and

the temperature lock control circuit (Figure 3.17) in the associated configuration register.

To each overload counter is a peak register associated. The value of the overload counters can not be retrieved

via the SPI port. However, the value of the overload counter will be copied in the related peak register if the value

of the overload counter is greater than the value of the peak register. The peak registers can be read via the SPI

port. The content of the peak register will be cleared after each read access. However, within the next cycle of the

IC control circuit the peak register will be set to the overload counter value again if this value is greater than zero.

The above described peak register update is only performed if an overload situation is present. In case of

overload situation the peak register is an important instrument to perform an IC diagnostic. For more information

about techniques to operate the peak, please refer to Appendix A.

A due to an overload raised internal exception will cause in case of over-current a lock of the related channel or a

lock of both channels in case of a over-temperature situation. There are three signals (displayed in status

detected an over-current or if the configured maximum of the die temperature has been exceeded.

ZIOL2201 Datasheet(PDF) 25 Page - Renesas Technology Corp