BWR-5/6-3.3/7-D12 Murata Power Solutions Inc, BWR-5/6-3.3/7-D12 Datasheet - Page 5

• Manufacturer Part Number: BWR-5/6-3.3/7-D12
• Description: DC/DC Power Supply Dual-OUT 5V/3.3V 6A/7A 33W 7-Pin Case C4
• Manufacturer: Murata Power Solutions Inc
• Type: Step Downr

Specifications of BWR-5/6-3.3/7-D12

• Package: 7Case C4
• Output Current: 6|7 A
• Output Voltage: 5|3.3 V
• Input Voltage: 12 V
• Number Of Outputs: 2
• Output Power: 33 W

Current Limiting
When power demands from either output fall within 126% to 181% of the rated
output current, the DC/DC converter will go into a current limiting mode. In this
condition both output voltages will decrease proportionately with increases in
output current, thereby maintaining a somewhat constant power dissipation.
This is commonly referred to as power limiting (see Figures 2a and 2b). Current
limit inception is defined as the point where the full-power output voltage
falls below the specified tolerance. If the load current being drawn from the
converter is significant enough, the unit will go into a short circuit condition.
See "Short Circuit Condition."
4
3
2
1
0
4.5
3.5
2.5
1.5
0.5
5
4
3
2
1
0
Typical Current Limiting Characteristics for 3.3V Output
0
Typical Current Limiting Characteristics for 5V Output
(3.3V Output @ 700mA)
0
Figure 2a. Current Limiting Characteristics for 3.3V Output
Figure 2b. Current Limiting Characteristics for 5V Output
1
2
V
All Models
V
Models
V
D48 Models
IN
IN
IN
NOM, V
HI D12, D24
HI
3.3 V
2
4
5 V
OUT
IN
OUT
LO
3
Average Ouput Current (Amps)
Average Ouput Current (Amps)
6
4
8
5
V
V
V
D48 Models
IN
IN
IN
www.murata-ps.com
NOM, V
HI D12, D24 Models
HI
6
10
IN
LO All Models
7
12
8
14
9
Short Circuit Condition
When a converter is in current limit mode the output voltages will drop as the
output current demand increases (see figures 2a and 2b). If the output voltage
drops too low, the magnetically coupled voltage used to develop primary side
voltages will also drop, thereby shutting down the PWM controller.
causing the output voltages to begin ramping to their appropriate values. If the
short-circuit condition persists, another shutdown cycle will be initiated. This
on/off cycling is referred to as “hiccup” mode. The hiccup cycling reduces the
average output current, thereby preventing internal temperatures from rising
to excessive levels. The BWR is capable of enduring an indefinite short circuit
output condition.
Thermal Shutdown
These BWR converters are equipped with Thermal Shutdown Circuitry. If the
internal temperature of the DC/DC converter rises above the designed operat-
ing temperature, a precision temperature sensor will power down the unit.
When the internal temperature decreases below the threshold of the tempera-
ture sensor the unit will self start.
Output Overvoltage Protection
Both output voltages are monitored for an overvoltage condition via magnetic
coupling to the primary side. If either output voltage should rise to a level which
could be damaging to the load circuitry, the sensing circuitry will power down
the PWM controller causing the output voltages to decrease. Following a time-
out of 5 to 15 milliseconds the PWM will restart, causing the output voltages to
ramp to their appropriate values. If the fault condition persists, and the output
voltages again climb to excessive levels, the overvoltage circuitry will initiate
another shutdown cycle. This on/off cycling is referred to as "hiccup" mode.
Isolation/Case Connection
The BWR 33 Watt Series’ 5V and 3.3V outputs (pins 5 & 7) and return (pin 6)
are isolated from the +V
an opto-coupled transistor. Case connections are made internal to the DC/DC
converter. "D12 & D24" cases are connected to –Input (pin 2), "D48" to +Input
(pin 1).
Following a time-out period of 5 to 15 milliseconds, the PWM will restart,
Dual Output BWR Models
Technical enquiries email: [e-mail], tel:
IN
and –V
Mixed Voltage, 5V
IN
inputs (pins 1 & 2) via a transformer and
MMDC_BWR 33W Models.A02
33 Watt DC/DC Converters
AND
3.3V, 2” x 2”
[phone]
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