uP6013

Conceptual

4

uP6013-DS-C3200, Jun. 2016

www.upi-semi.com

Functional Description

The uP6013 integrates an N-channel and P-channel

MOSFETs to realize a synchronous rectifier with a current

source of P-MOSFETs for output current regulation. The

power conversion efficiency is up to 90%. Since a typical

step-up converter has a conduction path from the input to

the output via the body diode of the P-channel MOSFET, a

specific circuit is used to reverse the polarity of the P-

channel body diode when the part is shutdown. It certainly

protects battery from being completely depleted during

shutdown.

Input Supply Voltage, V

IN

V

voltages. The supply voltage range is from 2.7V to 5V. A

power-on reset (POR) continuously monitors the input

supply voltage. The POR level is typically 2.5V at V

A minimum 47uF ceramic capacitor with shortest PCB

traces is highly recommended for bypassing the supply

input.

Current Limit Function

When the inductor current is higher than current limit

threshold, the current limit function activates and forces

the N-channel MOSFET to turn off the limit inductor current

cycle-by-cycle. If output voltage drops under 73% (Typ) of

setting, the short circuit protection (SCP) will be activated

and latch off the output of boost converter. To restart the

output after latch-off, please input enable signal again.

Output Voltage Setting and Feedback Network

The output voltage can be set from VFB to VOUT by a

voltage divider as:

⎟

⎠

⎞

⎜

⎝

⎛

+

×

=

4

3

1

R

R

V

V

FB

OUT

The internal VREF is 1.227V with 1.5% accuracy. In real

applications, a 22pF feedforward ceramic capacitor is

recommended in parallel with R3 for better transient

responses.

Output Current Control

The uP6013 is built-in with a current source of P-MOSFETs

for output current control. The P-MOSFETs can be turned

on or turned off to regulate output current through a PWM

input (PWM_CTL) or DC input (DC_CTL). It supports

external PWM input frequency from 1kHz to 100kHz, the

relationship between PWM_CTL with CS Duty can be shown

as Figure 1.

When using DC input control, the output current duty

corresponds to DC_CTL is 0.25~1.15V and the DC control

input voltage can be achieved by setting the ratio of R1 and

R2 resistors.

⎟

⎠

⎞

⎜

⎝

⎛

+

×

=

2

1

2

2

.

1

_

R

R

R

V

CTL

DC

Then the DC control input voltage corresponds to output

current duty can be shown as:

Duty

Current

Output

V

V

MIN

CTL

DC

MAX

CTL

DC

=

−

−

−

9

.

0

_

_

Where

Input range of V

Keep V

0.25V, the current source output will keep in minimum on

duty.

0

20

40

60

80

100

0

10

20

30

40

50

60

70

80

90

100

PWM_CTL = 1kHz

PWM_CTL = 100kHz

Fixed Mode

The uP6013 is implemented with a fixed 5V output voltage

function without the need of an external feedback voltage

divider. If the FB pin is shorted to GND during device start-

up, the uP6013 will automatically activate its internal

feedback network and regulate its output at 5V.

Over Temperature Protection (OTP)

The OTP is triggered and shuts down the uP6013 if the

is a non-latch type of protection. The uP6013 automatically

initiates another soft start cycle if the junction temperature

Thermal Fold Back

The thermal fold back function can monitor IC temperature

to keep heating wires continuously working. When the

into thermal fold back mode and current source duty cycle

will be set to 50% of normal operation to decrease output

current. The uP6013 will return to normal operation once

Figure 1. PWM_Duty vs. CS Duty

PWM_CTL Duty (%)