ACT510x
Rev 1.0, 04-Apr-2018
VOUT[10:0] voltage register. The ramp rate the output changes can be controlled by the OUTPUT_SLEW[1:0] register. This
allows the output to conform to QC2.0/QC3.0/4.0/USB PD functions for higher output voltages.
If external feedback is used, the reference voltage on FB is 2V. The COMP pin is used for the output compensation.
Input voltage must stay above VIN_UV set by VIN_UV Register 0x0F [7:5].
5.1. Enable Delay
Once the condition has the valid conditions for startup, the Enable Delay timer is enabled. The timer options allow an
immediate startup, or to wait between 200msec and 1sec before enables the converter. This timing is controlled by the
EN_DLY[1:0] register.
5.2. Mode Soft Start
After the Enable Delay has completed, the device starts the output using a soft start function programmable by the SS[1:0]
Register. The time is independent of the output voltage setting if using internal feedback and or resistor settings when using
external feedback.
5.3. Constant Current Output Regulation
After soft start is completed, the device monitors the current on sense resistor (OSRP and OSRN) to provide constant
current regulation. When the output current exceeds threshold the value configured by the OLIM Pin and CC Register, the
switching converter will regulate the maximum current in a “constant current” mode. In this case, the output voltage may
drop. Constant current mode can be monitored in real time using the read only Output_CC Register 0x20 [5].
The current can be controlled with the external resistor on the OLIM pin and by the CC [6:0] Register 0x17 [6:0]. Current is
adjustable as a percentage of the full current level set by the OLIM resistor.
ROSRP
OSRP
+
COCS
OSRN
-
ROCS
ROSRN
VBAT
2V
VOUT
+
OLIM
-
ROLIM
Figure 5: Charge Current Sensing and Current Limit Setting
This voltage on the OLIM pin is calculated by:
OLIM = ROCS x ICHG × ROLIM x 2x10-3
V
Equation 1
The voltage on this pin is regulated and clamped at 2V. The OLIM pin can also be used to monitor input current .The voltage
on OLIM pin is proportional to the charge current.
The filter cap COCS should be 470nF, and ROSRP and ROSRN should be 30Ω.
If the output drops below 2.72V, a fault on the output is assumed, and the converter will disable and wait 3 seconds in the
HICCUP state. After 3 seconds, the device will return to the Reset state and attempt to restart the output. If a short or high
current fault is present, it will cycle again through the states until the fault is removed.
5.4. Input Current Regulation
ACT510x monitors the current on input side sense resistor (ISRP and ISRN) to provide a current limit from the input. When
the input current exceeds threshold the value configured by the ILIM Pin and INPUT_ILIM Register 0x10 [3:2], the switching
converter will regulate the output current in a “constant current” mode. In this case, the output voltage may drop. Input
constant current mode can be monitored in real time using the read only INPUT_CC Register 0x20 [6].
13
ACTIVE-SEMI [ ACTIVE-SEMI, INC ]
