Picor Corporation www.picorpower.com
QPO-1-EVAL3 Data Sheet Rev. 1.1 Page 1 of 4
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QPO-1-EVAL3
QPO-1 Evaluation Board, Micro Foot Print DC-DC Converters
Description
The QPO-1-EVAL3 is designed to allow full testing of
the QPO-1 and its various performance settings to
optimize final system design. The board offers switch
settings for the user to select preset values for the
Rhr, Rsc, and Rsa resistors. Solder pads are available
to mount user-selected values of these components if
required. Please refer to the QPO-1 product data
sheet, and the following pages for the proper
application of this board. The EVAL3 accommodates
Vicor's quarter brick DC-DC converters with an input
up to 72 Vdc.
The QPO-1 output ripple attenuator SiP uses active
filtering to reduce output ripple and noise (PARD)
over 20 dB from 50 Hz to 500 kHz. The QPO-1
operates over a voltage range from 3 to 30 Vdc and
supports load currents as high as 10A. Output
regulation is maintained with remote sense or trim
adjustment of the power supply. The closed loop
architecture improves transient response and ensures
precise point-of-load regulation.
Other eval boards (see part numbering description)
allow easy evaluation with other DC-DC converters
or power supplies with standard terminations.
Note 1: For off-line supplies 20dB attenuation can be achieved
down to 50Hz with additional capacitance added from the
VREF pin to the REFGND pin.
Features of the QPO-1
>30 dB PARD attenuation, 1 kHz to 500 kHz
>20 dB PARD attenuation, 50 Hz to 500 Hz
1
10A rating over a 3-30 Vdc operating range
Supports precise point-of load regulation
Up to 99% efficiency with power limit protection
User selectable optimization of attenuation,
power dissipation & transient load response
Peak detector function optimizes for ripple
amplitude variation automatically
1.0 x 1.0 x 0.2" SiP with BGA or LGA mounting
Improves transient response of most DC-DC
converters and power supplies
Reduces required number of output capacitors
to support dynamic loads.
Patents Pending
Typical Application
QPO-1 Performance
Rhr
SC SET
CESR
QPO OUT
VREF
GND
SC
QPO IN
REFGND
QPO-1
Cout
Rsc
VOUT+
VOUT-
SENSE+
SENSE-
SC
LOAD+
LOAD-
Figure 1 SC/Trim supports applications that don't
require remote sense.
Figure 2 Typical performance with a 3.3 Volt converter.
QPO IN (AC)
QPO OUT (AC)
LOAD CURRENT (DC) 1A/DIV
QuietPower
TM
Picor Corporation www.picorpower.com
QPO-1-EVAL3 Data Sheet Rev. 1.1 Page 2 of 4
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28V = All Off
3.3V
5V
12V
10A Maximum
Bypass
Slope Adjust
EARTH/Baseplate
3V to 30V Input Voltage
-
-
+
PICOR QPO-1
Micro Application Board rev.2
Optional Transient
Capacitors
SW2:
2:
SC Capacitor
+
C8
SW2
SW1
R11
R10
C9
C5
VREF
R9
R8
R7
R6
R5
R4
R3
R1
External Load
Input Supply
COUT
SC
GND
C6
C7
C10
QPO IN
QPO OUT
SW3
SC Function
UP
DOWN
1:
IN
OUT
SC Control
Enabled Disabled
QPO-1
Supply+
Supply-
Earth
LOAD+
LOAD-
1
O
N
2
N
O
3
2
1
43
21
567
+
+
XXXXA
US AND FOREIGN PATENTS, PATENTS PENDING
PHIL
ENGINEERING SAMPLE
QPO-1
Figure 3 - EVAL3 Board layout and measurement locations.
QPO IN
QPO OUT
SC
VREF
R7
user defined
R1
user defined
COUT
15uF
QPO OUT
9
SLOPE ADJ
2
QPO OUT
7
SC SET
6
CESR
5
QPO OUT
8
QPO OUT
10
QPO OUT
17
VREF
3
GND
1
SC
16
PEAK IN
15
QPO IN
14
QPO IN
18
QPO IN
13
QPO IN
12
QPO IN
11
REFGND
4
GND
19
GND
20
QPO-1
RAM SIP REV1H
R6
optional
QPO IN
QPO OUT
VREF
1
2
3
Input Supply
1
2
External Load
C1
4.7nF
C3
4.7nF
C4
4.7nF
C2
4.7nF
BasePlate
BasePlate
SC
C5
100uF
SC SET
CESR
12
34
765
MH1
MH3
MH4
MH6
MH5
MH2
MICRO1
MICRO FOOTPRINT
C6
270uF
C7
270uF
R11
TBD
C9
TBD
1
12
2
11
SW1A
204-213ST
3
10
4
9
SW1B
204-213ST
5
8
6
7
SW1C
204-213ST
SC SET
VREF
QPO OUT
1
4
SW2A
204-2ST
2
3
SW2B
204-2ST
Supply+
Supply-
C8
optional
12V
5V
3.3V
R8
86.6K
R9
35.7K
R5
2.67K
R3
9.76K
R4
4.02K
R10
23.7K
C10
3.3uF
2
1
3
SW3
CAS-120B1
QPO IN
QPO OUT
GND
Figure 4 - Schematic of EVAL3
Picor Corporation www.picorpower.com
QPO-1-EVAL3 Data Sheet Rev. 1.1 Page 3 of 4
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Switch Tables
The QPO-EVAL3 board has been designed to
accommodate a wide range of output voltages from
a micro footprint DC-DC converter.
Switch 1 (SW1 in the lower-right corner of the pc
board) is used to set the appropriate headroom
voltage and SC current for converters with 12V, 5V
or 3.3 Vdc outputs. Optimal headroom and SC
current settings are pre-defined and the appropriate
components are populated on the board.
The board EVAL3 will also accommodate user
defined output voltages. With all SW1 switches in
the "down" position (open circuit), the switch
settings allow access to the open pads for R1 and R7.
The user must calculate a value for headroom
voltage setting resistor (R7) and the SC current
setting resistor (R1) and populate the pads with the
selected components. Originally, this position was
designed to be used with a 28V converter, hence the
reference to "28V - ALL OFF" on the pc board.
With the first switch of SW1 in the "up" position,
and the rest in the "down" position, the headroom
voltage and SC current setting is adjusted to work
with a 12V converter. With the second switch of
SW1 in the "up" position, the rest "down", the
converter is set to work with a 5V converter. With
the third switch "up", the rest "down", the board is
set to work with a 3.3V converter. This switching
network will parallel the switched in resistors with
R7 and R1. If a predefined voltage is to be used, R7
and R1 should not be populated. At no time should
more than one switch be in the "up" position to get
accurate results.
SW2 is used to engage the SC control function and
to add an additional bypass capacitor to the SC pin
of the converter. With the first switch of SW2 in the
"up" position, a 3.3uF capacitor (C10) is added to the
SC pin of the converter. With the second switch of
SW2 in the "up" position, the SC control circuit of
the QPO is connected to the converter. When the
switches are in the "down" position, the capacitor
and SC connection are opened and out of the circuit.
SW3 is used to engage the optional Slope Adjust
resistor when in the "up" position.
Instructions For Use
The terminal block in the lower left-hand corner of
the pc board (labeled "Input Supply") is used to
provide the input voltage to the DC-DC converter.
The output load should be connected to the
terminal block on the right, labeled "External Load"
and should not exceed 10 Amps.
The QPO application board has Johnson Jacks
mounted on three key measurement points. These
jacks greatly reduce the amount of radiated noise
that gets picked up by the ground clip leads of the
scope probes. QPO IN is the input to the QPO from
the DC-DC converter. QPO OUT is the output of the
QPO where effects of the various settings can be
analyzed. VREF is the reference voltage that the QPO
uses to maintain a desired output voltage.
A resistor from this pin to ground will determine
the QPO's operating headroom voltage (the voltage
drop between QPO IN and QPO OUT) according to
the following equation:
where;
Rhr is headroom resistor value,
QPOout is the voltage seen on the QPO's output,
Vhr is the target headroom voltage.
The Rsc resistor is tied between QPOOUT and SC SET
pin and sets the correction current used to trim up
the converter to maintain a constant output voltage
on the QPO's output. The value for the SC SET
resistor is calculated by the following equation:
where;
Rsc is SC SET resistor value,
Rin is the input resistance of the SC or TRIM,
Vout is the source output voltage,
Vrpt is the pre-trimmed reference of the
SC or TRIM.
On the application board there are two spots for
additional capacitors (C6 and C7) to be added to the
QPO's input. These might be required if higher
transient steps are needed from higher output
voltage converters. These converters typically have
lower output capacitance than lower output voltage
converters do.
Rhr =
QPOout
* 2.5k
Vhr
Rsc =
Rin * Vout
Vrpt
Picor Corporation www.picorpower.com QPO-1-EVAL3 Data Sheet
P/N 27091 Rev. 1.1 9/03/10M
Vicor's comprehensive line of power solutions includes high-density AC-DC & DC-DC
modules and accessory components, fully configurable AC-DC & DC-DC power supplies,
and complete custom power systems.
Information furnished by Vicor is believed to be accurate and reliable. However, no responsibility is
assumed by Vicor for its use. No license is granted by implication or otherwise under any patent or
patent rights of Vicor. Vicor components are not designed to be used in applications, such as life
support systems, wherein a failure or malfunction could result in injury or death. All sales are subject
to Vicor's Terms and Conditions of Sale, which are available upon request.
Specifications are subject to change without notice.
Vicor Corporation
25 Frontage Road, Andover, MA, USA 01810
Tel: 800-735-6200 Fax: 978-475-6715
Email
Vicor Express: vicorexp@vicr.com
Technical Support: apps@vicr.com
Part Number
Description
QPO-1-EVAL3
Evaluation board for QPO-1
for Micro footprint DC-DC
Converters
Ordering Information
R11 and C9 are used for filtering the input to the
QPO's peak detector input. The QPO's peak detector
circuit will increase the headroom of the QPO by
roughly half of the peak-to-peak ripple on the QPO's
input. At low input voltage, the added headroom
might cause the SC circuit to trim up a converter to a
point where it shuts down due to an over-voltage
fault.
There is a spot for adding an addition capacitor to
VREF (C8) if greater attenuation is needed at lower
frequencies.
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