L99H01
Symbols:
• x: Don't care
• 1: Logic high or active
• 0: Logic low or not active
• H: Output in source condition
• L: Output in sink condition
• RL: Resistive low (see Section 3.4)
• T: Tristate
• FW: Free wheeling
• FW_PAS: Free wheeling passive
• CP_LOW: Charge pump low
• OV: Overvoltage
• UV: Undervoltage
• SC: Short-circuit
• TSD: Thermal shutdown
• GL_ER: Global error flag
Device description
3.4
Resistive low
The resistive output mode protects the L99H01 and the H-bridge in the standby mode and in
some failure modes (internal and external thermal shutdown (TSD), charge pump low
(CP_LOW), stucked reset (STK_RESET_Q) and power-on reset (PORES). When a gate
driver changes into the resistive output mode due to a failure a sequence is started. In this
sequence the concerning driver is switched in sink condition for 32 µs to 64 µs to ensure a
fast switch-off of the H-bridge transistor. Afterwards the driver is switched in the resistive
output mode (resistive path to source).
3.5
Diagnostic functions
The diagnostic functions (over load, power supply over- and undervoltage, charge pump
low, watchdog, temperature warning and internal/external thermal shutdown) are internally
filtered and the condition has to be valid for at least 64 µs (6 µs for a short-circuit) before the
corresponding status bit in the status registers is set. The filters are used to improve the
noise immunity of the device. The internal temperature warning function is intended for
information purpose and does not change the state of the output drivers. On the contrary,
the over load condition switches the corresponding halfbridge in sink condition. The internal
thermal shutdown condition and charge pump low disable all drivers (resistive low). The
external thermal shutdown, watchdog, over- and undervoltage condition switch all driver in
sink condition. The microcontroller needs to clear the status bits to reactivate the drivers.
3.6
Overvoltage and undervoltage detection
If the power supply voltage VS rises above the overvoltage threshold VVS_OVH
(typical 20 V / 30 V), all gate driver stages are switched in sink condition to protect the
H-bridge and the load, setting the OV bit. Two values for the overvoltage threshold can be
selected with the SPI. When the voltage VS drops below the undervoltage threshold
DocID15567 Rev 5
27/53
52