TPSM846C23: TPSM846C23MOLR Power Module Stackable for 70A

Hey Sujith,

You can still use PMBUS functionality in a design that has 2 modules stacked. Please see the datasheet.

The Vout step size of the device can be seen in the electrical characteristics table of the datasheet. The device is capable of less than 10mV vout step. See below.

Thanks,
Caleb

Hi Caleb,

Thanks for your reply.

I have few more query regarding this power modules.

1) How do we control the devices via PMBUS?for stacked mode there are two power modules,how to select the PMBus address, How can we acess the power modules in stacked mode?

2)The datasheet shows the transient current response, but this is for non stacked mode. What would the transient response be in stacked mode?

3)Do the configuration resistors and caps change in stacked mode(Vout programming through external resistor... Etc?

4)How do we ensure that the transient response and the ripple are the lowest possible in both stacked and non stacked mode?

Thanks,

Sujith M

1) Please see datasheet section 7.3.1.2. The address is selectable through connecting resistors from the ADDR0 and ADDR1 pins to AGND. Each device should have it's own unique address. 

Each resistor in this table assigns a level. The equation to translate this into a PMBUS Address (decimal) is: PMBus Address = 8 × ADDR1(level) + ADDR0(level).

Assuming they are on the same bus, you would access them by addressing them appropriately.

2. Generally, having parallel devices doesn't have too much of an effect on transient performance. Parallel applications are generally used for high current applications. 

3. Parallel application is detailed in section 7.3.19 of the datasheet.

4. For this part, the compensation network is the most important aspect of ensure that your device is running at it's best performance. Section 7.3.3 outlines compensation component selection dependent on your switching frequency and Cout. Section 7.3.4 provides a summary of transient response for different switching frequencies and Cout values.

Thanks,
Caleb

Hi Caleb,

1)In stacked 70A high current design , there will be 2 power modules(master and slave modules )in a single PMBus. How do we assign address to each modules?How can we program the PMIC?

4)Section 7.3.4 Table 4, which compensation network values has to be selected for below requirement?

Design 1

• Vin=5V   Vout=0.65V @70A

Design 2

• Vin=5V  Vout=0.75V @70A

Regards,

Sujith M

Sujith,

I understand that there will be two power modules. Simply pick resistor values that result in different PMBUS addresses. It is arbitrary, but they cannot be the same.

The design depends on what kind of transient response you want. BOM savings you should use line two for Vout = 0.65V, and the sixth line for Vout = 0.75V.

Cost savings but worse performance you should use line one for Vout = 0.65V, and line 5 for Vout = 0.75V.

Thanks,
Caleb