E
ESKEVIN
3/1301-BMR 637 02 Uen
236
Technical Specification
Approved
Checked
Date
Rev
EN/LZT 146 3R0e6feRre4nAceJuly 2008
PKM 4000D PINB Series
SEC/D (Julia You)
EYINGJI
2007-12-10
B
© Ericsson Power Modules AB
DC/DC converters, Input 36-75 V, Output 40 A/132 W
Thermal Consideration continued
Connections
Definition of reference temperature (Tref
)
The reference temperature is used to monitor the temperature
limits of the product. Temperatures above maximum Tref are
not allowed and may cause degradation or permanent
damage to the product. Tref is also used to define the
temperature range for normal operating conditions.
Tref is defined by the design and used to guarantee safety
margins, proper operation and high reliability of the module.
Ambient Temperature Calculation
By using the thermal resistance the maximum allowed
ambient temperature can be calculated.
Top View
1. The power loss is calculated by using the formula
((1/η) - 1) × output power = power losses (Pd).
η = efficiency of converter. E.g 90 % = 0.90
Pin
Designation
+In
Function
Positive input
1
2
3
4
5
6
7
8
RC
Remote control
2. Find the thermal resistance (Rth) in the Thermal Resistance
graph found in the Output section for each model.
Calculate the temperature increase (ΔT).
ΔT = Rth x Pd
- In
Negative input
- Out
- Sen
Vadj
+ Sen
+ Out
Negative output
Negative remote sense
Output voltage adjust
Positive remote sense
Positive output
3. Max allowed ambient temperature is:
Max Tref - ΔT.
E.g PKM 4110D PINB 53v full load at 2m/s:
1
1. ((
) - 1) × 115 W = 14.2 W
0.89
2. 14.2 W × 4°C/W = 56°C
3. 110 °C - 56°C = max ambient temperature is 54°C
The real temperature will be dependent on several factors, like
Pcb size and type, direction of airflow, air turbulence etc.
It is recommended to verify the temperature by testing.
ERICSSON [ ERICSSON ]
