MPQ18913

– 30V, 0.3A High Frequency Transformer Driver

PRELIMINARY SPECIFICATIONS SUBJECT TO CHANGE

MPQ18913 Rev. 0.8

MonolithicPower.com

10

12/8/2021

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

Preliminary Specifications Subject to Change

© 2021 MPS. All Rights Reserved.

OPERATION

Enable Control (EN/SYNC)

The EN pin enables and disables the MPQ18913

power converter. When applying a voltage

higher than the EN start up threshold the

MPQ18913 is enabled and starts switching

operation after a delay. The device is disabled

when the EN voltage falls below the turn off

threshold. EN pin is compatible with voltage up

to 30V, for automatic startup, connect EN pin to

VIN pin directly.

EN/SYNC pin can also be used for external clock

synchronization.

Connect

a

clock

with

a

frequency between 400kHz to 1.67MHz to

EN/SYNC pin, the internal clock will scale to be

1x, 3x the external clock while keep operating at

50% duty cycle. The scale factor is set by the

resistance placed at the FREQ pin.

SYNC

Freq

Scale Factor

Output

Freq.

Range

Resistance

at FREQ Pin

1

0.4-1.5MHz

100k

3

1.5-5MHz

33.2k

Under Voltage Lock Out

MPQ18913 implements under voltage lock out

(UVLO) on VIN and VCC pins separately. the Vin

UVLO rising threshold is as low as 4.9V max so

it allows for a direct start-up at wide Vin range.

Note the FLT pin will always be low in VIN or

VCC UVLO states.

Soft-Start of Power Converter

Upon start-up, the switching frequency starts at

2 times the set frequency in order to limit the

inrush current, and then gradually decreases to

the set value.

VIN

EN

SW

Resonant Freq

Detection

Soft-Start

Operation

tEN_ON_DELAY

tSS

Figure 2: Timing Diagram During Start-up

Over Current & Short Circuit Protection

The MPQ18913 implements a two levels over-

current

protection

scheme

on

the

power

converter. First level OC is implemented by

measuring the instantaneous current on the low

side FET. When the current rises above the OC

threshold, switching frequency will increase to

limit the input current. If the OC condition

persists for longer than 1ms, the part will stop

switching, pull low the FLT pin and auto-retries

after a waiting time tHICCUP. Upon auto-retry, FLT

pin will be released.

IIN

FLT

SW

Soft-Start

Operation

tOCP

ILIM

tSS

OC

blanking

OC

Shutdown

tHICCUP

Figure 3: Timing Diagram During Over Current

Event

The second level of the protection scheme

(SCP) senses the instantaneous input current

on high side FET. It is used to protect against

the dead short from SW to GND.

Over Voltage Protection

When input voltage goes above the over voltage

protection threshold, the converter immediately

stops switching and pull low FLT. After the input

voltage falls below the OVP threshold (with

hysteresis), the part re-starts and releases FLT.

Over Temperature Protection

MPQ18913

consistently

monitors

the

die

temperature. When the die temperature goes

over the thermal shutdown limit, the part stops

switching

and

pulls

low

FLT.

After

the

temperature falls back below thermal limit (with

hysteresis), the part restarts and releases FLT.

FLT Reporting

FLT pin is an open-drain output. The FLT pin will

be pulled low in the following conditions: Vin

UVLO, Vcc UVLO, OCP hiccup/latch-off, SCP

hiccup/latch-off, OVP, OTP.