MP5032

– QC 3.0 CONTROLLER WITH CURRENT-LIMIT SWITCH

MP5032 Rev r1.0

www.MonolithicPower.com

13

8/4/2017

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© 2017 MPS. All Rights Reserved.

In no-load condition, if the input voltage is lower

than the typical 5.1V, ADJ sinks a current to

regulate the upstream regulator's output voltage

to 5.1V. If the input voltage is higher than 5.1V,

the MP5032 no longer regulates the input

voltage.

Figure 3 shows the typical ADJ usage. The ADJ

sink current capability is 500µA. The feedback

current through R1 must be less than 500µA.

Calculate R1 with Equation (1):

 

0.5

(V)

V

(V)

V

k

R1

FB

OUT







(1)

be adjusted to.

IN

ADJ

MP5032

C1

Converter

OUT

FB

R1

R2

Figure 3: ADJ Configuration

Input Over-Voltage and Discharge

To protect the downstream device from an

over-voltage condition, the MP5032 provides an

input over-voltage protection (OVP) shutdown

function. Since the MP5032 supports QC 3.0

protocol, it has a dynamic OVP threshold.

An accurate and fast comparator monitors the

over-voltage condition of the input. If the input

voltage rises above the threshold, the gate of

the internal MOSFET is pulled low quickly, and

the power MOSFET is shut down. At the same

time, the input-to-ground discharge path is

active. When input voltage falls below the

typical 5.5V, the MP5032 exits OVP mode.

The OVP shutdown function is blanked during

the high-to-low voltage mode change period.

The input-to-ground discharge resistance is

always active during the high-to-low voltage

mode change period. The discharge path is

with 20ms of additional delay (see Figure 4).

t

V

Discharge

Enable

20ms

Figure 4: Input Discharge during High Voltage to

Low Voltage Transition

QC mode is reset during the OVP rising edge.

Over-Current Protection (OCP)

The MP5032 provides a constant current limit.

The current-limit threshold is adjustable by an

external resistor.

Once

the

device

reaches

its

current-limit

threshold, the internal circuit regulates the gate

voltage to hold the current in the power

MOSFET constant.

The MP5032 supports different voltage modes.

Table 2 shows the over-current threshold for

each case. Figure 5 shows an example of the

current limit versus the bus voltage curve.

Table 2: OCP Threshold vs. Bus Voltage

USB Bus

Voltage

Mode

Over-Current

5V

(actually 5.1V)

BC1.2 or

QC 2.0

4.8

9V

QC 2.0

4.08

12V

QC 2.0

3.12

3.6V - 6.4V

QC 3.0

4.8

6.6V - 9.6V

4.08

9.8V - 12V

3.12

The current-limit threshold can be calculated

with Equation (2):

)

Ω

(k

R

V

(A)

I

LIMIT

LIMIT

LIMIT



(2)

accuracy cannot be guaranteed.