DA9233 datasheet(24/50 Pages) RENESAS

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DA9233

Integrated Ultra-Low Quiescent Current, Ultra-Low

Output Ripple Buck Regulator with 100 mA LDO

Datasheet

Revision 2.2

13-Jun-2023

CFR0011-120-00 Rev 5

24 of 50

10.4.3

Power Saving Mode Operation

DA9233 buck regulator features power saving mode that greatly reduces the quiescent current when

device has very light load condition. Buck regulator operates in discontinuous mode with Pulse

Frequency Modulation (PFM). The low-side FET will be turned off based on a zero-crossing

comparator to prevent negative inductor current flowing through the FET which can result in

additional conduction loss. If both FETs remain in the OFF state for a certain delay time after inductor

current crosses zero, the device will enter power saving mode. In power saving mode, DA9233 shuts

down most of the internal circuitry to save current consumption. The lighter the load, the longer the

duration of power saving mode will be, to achieve the lowest quiescent current and improve light load

efficiency.

10.4.4

Dynamic Voltage Control

DA9233 buck regulator has dynamic voltage control (DVC) feature which allows the buck output

voltage to track the internal reference voltage when it changes at a rate of 50 mV / 2 ms. Since the

buck output voltage can only be changed within an allowable range while still keeping the buck

enabled, DVC also follows the same behaviour. The DVC is done via I2C, whereby the buck output

voltage setting is stepped in 50 mV steps within either the low range or high range. Each voltage step

lasts for 2 ms.

10.4.5

Cycle-by-cycle Over-Current Protection

For the Over-current Protection (OCP) in DA9233, the peak current through high-side FET is

monitored cycle-by-cycle. When the sensed current exceeds the pre-set current limit, the high-side

FET will be turned OFF immediately to limit the inductor current. The high-side FET will be turned on

again after the constant-off time expires. If the OC condition persists for 64 µs, buck will be forced off

and buck output will be pull-down until the fault clears, see Section 10.4.9 for fault behavior and

control and Section 10.4.8 for output voltage discharge and control. An OC_BUCK_Event will be

flagged if it is not masked.

10.4.6

Output Over-Voltage Protection

DA9233 features an output over-voltage protection (OVP) to protect the load from damage. When

both IC_EN and BUCK_EN are high and the buck output voltage is 200 mV greater than the internal

reference voltage, the high side FET is immediately OFF, see Section 10.4.9 for fault behavior and

control. Then the internal buck output discharge FET will be turned on to discharge buck output

capacitor, see Section 10.4.8 for output voltage discharge and control. An OV_BUCK_Event will be

flagged if it is not masked. Buck will remain off and buck output will be pull-down until the fault is

cleared.

10.4.7

Output Under-Voltage Protection

When buck output short happens, inductor current will increase until the peak reaches the cycle-by-

cycle current limit. Then the high-side FET turns OFF and low-side FET turns on. Since buck output

is shorted, inductor current slope is very small during low-side FET on time. The inductor current

could gradually go higher and higher. To effectively prevent the inductor current running away at VOUT

short condition, buck VOUT is also monitored. If over-current condition happens and buck VOUT drops

400 mV below the reference voltage, the buck regulator will be shut off immediately and an

UV_BUCK_Event will be flagged if it is not masked, see Section 10.4.9 for fault behavior and control.

DA9233 Datasheet(PDF) 24 Page - Renesas Technology Corp

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