200A Current Sink for VRM Load Transient Testing

[nebo123]

I need a 200Amp active current sink tester/circuit to do VRM (multiphase) load transient tests, ( i.e. similar to Intel’s VRM12/12.5 specification with current load step transients 20% to 80 % UP and 80% to 20 % DOWN with slew rates in excess of 1000A /usec; Intel sells VTT Gen3/4 test tool to do this but it is very $$ expensive) ) , late Jim Williams published an App Note in EDN to this end with 100A capability (see link below, Figure 5 ) , how can I modify this circuit to achieve
200A current sink capability, any other suggestions/circuits are welcome.

http://cds.linear.com/docs/en/application-note/an133f.pdf

see also;
http://cds.linear.com/docs/en/application-note/an104f.pdf
http://www.edn.com/design/analog/4319132/Load-transient-response-testing-for-voltage-regulators
**broken link removed**