SLLSFE8B November 2024 – November 2025 TCAN2845-Q1 , TCAN2847-Q1
PRODUCTION DATA
These pins are based upon a high-side switch configuration supporting load current up to IOC(HSS). The control method for each HSSx is accomplished by programming the HSS_CNTL (8'h1E) and HSS_CNTL2 (8'h4D). This control includes any of four PWM settings, two timers, always on/off or direct drive from the WAKE3/DIR pin. The four 10-bit PWMs support 200Hz or 400Hz and can be assigned to any HSSx. To configure PWM3 and PWM4 SBC_CONFIG0 register 8'h0C[5:4] needs to be set to 01b. Once this is set, use the PWM1 and PWM2 configuration registers for programming PWM3 and PWM4. This changes the PWM1 control registers to PWM3 and the PWM2 control registers to PWM4. After configuring the registers, change 8'h0C[5:4] = 00b; thus, converting the PWM registers back to PWM1 and PWM2. The timers are configured using TIMERx_CONFIG registers 8'h25 and 8'h26.
Any HSS can be connected to any other HSS and synchronized by assigning them the same control mechanism. This allows higher current loads to be used. Assigning PWM1 to HSS1 - HSS4 synchronizes all four high-side switches. Timer1 and Timer2 can be used the same way. For the ability of the MCU to drive the HSSx directly, a direct drive capability using WAKE3/DIR pin is used. The high-side switches can be synchronized using direct drive by programming 1000b to the appropriate HSSx_CNTL fields.
When programing the high-side switches, the following procedure must be used:
HSSx starts as soon as the on-time is programmed.
The high side switches are monitored for open loads and over-current faults. When an over-current is detected through an HSS, there is a filter time, tOCFLTR, to determine if over-current is valid. If valid, a corresponding HSSx over-current interrupt flag is set in the INT_7 register 8'h55. If the over-current condition persists for tOCOFF, the HSS is turned off and HSSx_CNTL register is reset to 000b. HSS is not turned back ON automatically. HSS can be turned ON again after another tOCOFF period by writing into the corresponding HSSx_CNTL register. If the over-current fault is cleared, HSS stays ON. If the over-current fault exists, HSS is shutoff after tOCOFF. When an open load fault is detected at an HSS, an interrupt flag is set in the INT_7 register 8'h55. HSS is not turned off due to open load fault. Please note that HSSx over-current or open load fault interrupt flags are not automatically cleared after the fault is cleared.
The VHSS pin is also monitored for a high-side switch over-voltage condition based upon OVHSS thresholds. If VHSS exceeds this threshold the high-side switches are turned off. When VHSS drops below this threshold the high-side switches is automatically enabled to the previous state. Register 8'h4F[7:6] disables the high-side switches from automatically shutting down due to an OVHSS or UVHSS event. HSS_OV_UV_REC, register 8'h4F[5] = 1b enables the high-side switches to go back to the programmed state. If HSS_OV_UV_REC = 0b, the high-side switches stay off due to an over-voltage or under-voltage event on VHSS.
HSS4 can be configured to use one of two timers that allows HSS4 to work with WAKE1, WAKE2 and WAKE3 pins supporting cyclic sensing. Cyclic sensing can be used in standby or sleep mode thus reducing mode current due to the HSS being constantly on.