MP023 – PRIMARY-SIDE CC/CV CONTROLLER

MP023 Rev. 1.1

www.MonolithicPower.com

15

7/18/2016

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

© 2016 MPS. All Rights Reserved.

Figure 9: The External Configuration of CP

The entire customization process is completed

before start-up and latched in a register, so it

does not have any influence on normal

operation.

0 Ω/NC

*

0.4

10 kΩ/NC

0.3

20 kΩ/NC

0.35

40 kΩ/NC

0.5

NC/1μF

0.4

Notes:

* NC means no connection.

relationship between the output constant

be calculated with Equation (7):

ons

out

pks

pks

S Max

ons

offs

t

11

II

I D

2t

t

2







(7)

When the secondary diode is turned on, the

peak current on the secondary side is

calculated with Equation (8):

p

pks

PK

S

N

II

N



(8)

The output current is then calculated with

Equation (9):

p

out

PK

S Max

S

N

1

II D

2N





(9)

To implement the OLP function in CC mode,

the sampling on the FB voltage continues

Leading Edge Blanking

Turning the power switch on induces a spike on

the sense resistor. The MP023 employs a

falsely terminating the switching pulse. During

this

blanking

period,

the

current

sense

comparator is disabled, and the part cannot be

turned off.

DCM Detection

The MP023 is designed to operate in

discontinuous conduction mode (DCM) in both

CV and CC modes. To avoid operating in

continuous

conduction

mode

(CCM),

the

MP023 implements a zero current detection

(ZCD) function internally with a threshold of

ZCD is detected.

During normal operation, the blanking time for

ZCD is synchronized with the FB sampling time

(i.e., ZCD always starts after the sampling

phase is done). There is also a soft-start

function on the ZCD blanking time to prevent

ZCD from being triggered falsely when the

output capacitor is not charged up. During the

start-up period, the blanking time for ZCD

sampling time in 3 cycles.

OVP, OCkP, and OLP

The MP023 includes over-voltage protection

(OVP), open-circuit protection (OCkP), and

overload protection (OLP). If the voltage on FB

cannot be monitored for each cycle, OCkP is

triggered. If the sampled FB voltage is lower

triggered. When any of these protections are

triggered, the MP023 shuts off immediately,

enters hiccup mode, and resumes normal

removed.

OLP is not enabled until the soft-start period of

the ZCD blanking time is finished.

Over-Temperature Protection (OTP)

When the temperature of the IC exceeds 150°C,

the over-temperature protection (OTP) is

activated, and the IC enters auto-recovery

mode. When the temperature falls below 120°C,

the IC resumes operation.